The fifth season of American Idol began on January 17, 2006; this was the first season of the series to be aired in high definition. Auditions were in Austin, Boston, Chicago, Denver and San Francisco, with Greensboro, North Carolina and Las Vegas, Nevada included after the cancellation of the Memphis auditions due to Hurricane Katrina. The season used the same rules as Season 4.

Taylor Hicks was named American Idol on May 24, 2006; he was the third contestant to never fall into any week's "bottom three". His first post-Idol single, "Do I Make You Proud", would debut at #1 and be certified gold. Hicks' album, Taylor Hicks, has sold 690,000 copies to date.

On May 30, 2006, Telescope announced that a total of 63.5 million votes were cast in the finale round. A total of 580 million votes were cast in the entire season.Taylor Hicks is the second American Idol winner from the city of Birmingham, Alabama (the first being Ruben Studdard), and the fourth finalist with close ties to the city. The finale had surprise performances from stars such as Live, Mary J. Blige, and Toni Braxton singing duets with the members of the final 12. The unannounced appearance and live performance of Prince was said in the media to have perhaps signaled the music industry's acceptance of Idol as a promotional tool for established artists as well.

The fifth-season contestant with the most commercial success is fourth-place finisher Chris Daughtry, now lead singer of the band Daughtry. Their eponymous debut album has sold over 3.2 million copies to date - surpassing former winners Studdard and Fantasia's respective two-album totals - and produced three top-ten singles. The album, which spent two weeks at #1 in the US, is also the fastest-selling debut rock album in Soundscan history.

Runner-up Katharine McPhee's debut album has sold 350,000 copies; she has two Top 40 Billboard hits to date. Also notable: sixth-place finisher Kellie Pickler, whose Small Town Girl reached #1 on the Billboard Top County Albums chart, selling 600,000 copies to date with two Top 15 Country Songs to date; strong early sales have also been achieved by mid-2007 eponymous album releases by third-place Elliott Yamin and eighth-place Bucky Covington.

The fourth season of American Idol premiered on January 18, 2005. It was the first season in which the age limit was raised to 28, in order to increase variety. All Season 4 contestants had to be between the ages of 16 and 28 on August 4, 2004, born on or between August 5, 1975 and August 4, 1988. Among those who benefited from this new rule were Constantine Maroulis (born September 17, 1975) and Bo Bice (born November 1, 1975), considered to be the eldest and somewhat most experienced of the season's Idol contestants. They were also constantly mentioned by Seacrest and in the media as "the two rockers", since their long hair and choice of rock songs made them stand out from conventional Idol standards. The presence of more rock-oriented contestants has continued with Chris Daughtry in Season 5, who was inspired to audition for the show by Bice.

This season also implemented new rules for the final portion of the contest. Instead of competing in semi-final heats in which the top vote-getters are promoted to the final round, 24 semi-finalists were named; 12 men and 12 women, who competed separately, with 2 of each gender being voted off each week until 12 finalists were left.

Mario Vazquez, who was originally one of the top 12, dropped out of the competition on March 11, just days before the top 12's first performance, citing "personal issues", opening a spot in the final 12 for Nikko Smith (son of Baseball Hall of Famer Ozzie Smith), who had been voted off in the semi-finals the previous week.

The winner was Carrie Underwood, a country singer, the first winner since Kelly Clarkson to not only win but avoid being in the bottom three for the entire competition. Carrie Underwood's first single, "Inside Your Heaven", was released on June 14, 2005. The single debuted at #1 on the Billboard Hot 100, with first-week sales of 170,000 copies, and briefly stopped Mariah Carey's run at #1 with "We Belong Together". One week later, runner-up Bo Bice released his version of the song, which debuted at #2. The B-side of Underwood's CD was "Independence Day", a cover of the Martina McBride hit. On November 15, 2005, Carrie released her debut album, Some Hearts, which peaked and debuted at #2 on Billboard. It has currently sold over 5 million copies, and has gone 6X platinum. Underwood's first single, "Jesus, Take The Wheel" was made available for radio airplay on October 18, 2005. It received so much airplay that it debuted at #39 on the Billboard Country Chart in its first week, setting a record. As it climbed, it finally reached #1 for 6 consecutive weeks, just two weeks shy of Connie Smith's record of an 8 week run back in 1964-1965. The single also debuted at #48 on the Billboard Hot 100 where it peaked at #20. Underwood's second single, "Don't Forget to Remember Me", peaked at #2 on the Billboard Hot Country Charts, as well as, #49 on the Billboard Hot 100. Underwood's third single "Before He Cheats" not only hit #1 on the Billboard Hot Country charts, but also has peaked at #8 on the Billboard Hot 100 becoming a crossover pop hit. Currently, Underwood has the most successful debut album sales out of the American Idol finalists. Some Hearts has sold over 5 million copies as of January 2007, beating the previous most sales 2nd place record held by Clay Aiken's Measure of a Man, which sold 2.7 million copies. Underwood's fourth single "Wasted" has become her 3rd #1 single on the Billboard Hot Country Songs chart and also peaked at #37 on the Billboard Hot 100.

Bo Bice's first single "The Real Thing" has appeared on American Top 40 radio. Although Bice's sales did not match that of Underwood, he stands as the third-most successful recording artist to not win the American Idol title with RIAA platinum status. Third-place contestant Vonzell Solomon landed a role in a film, Still Green and a single on a Christmas album. Fourth-place contestant Anthony Fedorov has appeared in television shows such as Fear Factor, where he competed with Season 2 contestant Carmen Rasmusen, winning second place, and has finished taping several episodes for a new MTV show to air in the fall. Federov will be performing in The Fantasticks on off-Broadway May through July of 2007. Sixth-place contestant Constantine Maroulis has redone his rendition of "Bohemian Rhapsody" for a Queen tribute album, and his first solo debut will come out in early 2007. Since August 2006, Maroulis has appeared in the Broadway musical The Wedding Singer and the now closed off-broadway play Jacques Brel is alive and well and living in Paris. Seventh-place contestant Anwar Robinson has released his self-titled EP on an independent label. Twelfth-place contestant Lindsey Cardinale's first single, "Nothing Like A Dream", was released in March 2006.

In May 2005, Telescope announced that the fourth season had a total of approximately 500 million votes.

On February 11, 2007, Carrie Underwood became the first winner of American Idol to sweep all three major music awards (American Music, Billboard, and Grammy Awards) in a single season (for 2006-07).

The third season of American Idol premiered on January 19, 2004. The winner of this season of American Idol was Fantasia Barrino, later known professionally as simply "Fantasia," and the runner-up was Diana Degarmo. This was also the season that Golden Globe Award-winning and Academy Award-winning actress Jennifer Hudson was discovered.

The early part of the season introduced William Hung, a UC Berkeley student, who received widespread attention following his off-key rendition of Ricky Martin's "She Bangs." His performance, as well as his positive attitude facing Simon's criticisms (a stark contrast to other contestants' confrontational, angry reactions), landed him a record deal with Koch Entertainment and made him over $500,000 in record sales. He also starred in a Cingular Wireless commercial with host Ryan Seacrest.

During the season, controversy over the legitimacy of the contest increased as rocker Jon Peter Lewis and young crooner John Stevens stayed afloat while others were unexpectedly eliminated. Jasmine Trias, despite negative comments from Simon Cowell over her later performances, survived elimination and took the third spot over Latoya London. Trias later released a CD and attracted fans in her home state of Hawaii, the Philippines, Singapore, Guam and other South East Asian countries. The third season was also shown in Australia on Network Ten about half a week after episodes were shown in the U.S.

After a nationwide vote of more than 65 million votes in total - more than the first two seasons combined - Fantasia Barrino won the American Idol title over runner-up Diana DeGarmo. She released her first single in June 2004 on the RCA record label. The single included "I Believe" – cowritten by former Idol contestant Tamyra Gray (who also sang backup) – which Fantasia performed on the finale of Idol, the Aretha Franklin hit "Chain of Fools" (released before on an American Idol compilation), and her signature version of "Summertime". The single entered the Billboard Hot 100 at #1, making Fantasia the first artist in the history of Billboard to debut at number one with their first single. The song remained at the number one for one week (it topped the sales chart for 11 weeks in the US and 10 weeks in Canada). Fantasia's CD, I Believe, went on to become the top selling single of 2004 in the U.S and has since been certified double platinum by the CRIA and received 3 Billboard Music Awards. In 2006, she received 4 Grammy nominations for her double platinum debut album Free Yourself.

Sales of Diana DeGarmo's first CD, Blue Skies, suffered partly from a lack of promotion by RCA. DeGarmo eventually asked to be released from her RCA record contract. She received a role in the Broadway production of Hairspray, where she played the part of Penny Pingleton from February 7-May 21 to positive reviews. DeGarmo then starred with Melba Moore in the national tour of Brooklyn the Musical through mid-August. On September 8, she returned to the Broadway production of Hairspray to once again assume the role of Penny Pingleton for a six month period. DeGarmo is also working independently on a second album while performing in the musicals.

Second Runner-up Jasmine Trias signed with an independent label. Although she has failed to achieve commercial success in the mainland USA, she has become a major celebrity in other countries, such as the Philippines and Japan, where she is signed with Universal Records.

Latoya London signed with Peak Records and released an R&B/soul album, "Love & Life," selling 55,000 copies. Her single, "Appreciate/Every Part of Me/All by Myself," charted at number 8 on the Billboard Singles Sales Chart, and her songs, "Appreciate," "Every Part of Me," and "State of My Heart," all received moderate success on urban and adult contemporary radio. She starred in the Los Angeles revival of the retro-musical, "Beehive," and also starred with Angie Stone and Kim Fields in the tour of the play, "Issues: We All Got 'Em." Latoya will begin playing the role of Nettie in the touring edition of the Broadway musical, The Color Purple, which will begin with an extended run in Chicago, Illinois in April, 2007. The musical also stars Michelle Williams of Destiny's Child.

George Huff signed with Word Records to release a gospel album and has since had mild success in that genre. John Stevens landed a deal with Maverick Records but was dropped due to low album sales.

Jennifer Hudson starred alongside Beyoncé Knowles and Jamie Foxx in the 2006 feature film Dreamgirls and won several honors and awards, including a Golden Globe for her performance and an Academy Award for Best Supporting Actress. The film, which also won the Golden Globe for Best Picture (Comedy or Musical), was released to preview audiences on December 15, 2006, in New York, San Francisco and Los Angeles, drawing sellout crowds. On its first day in wide release (Christmas Day 2006), Dreamgirls sold 8.8 million dollars worth of tickets to claim the top spot at the box office. It was the single highest daily gross for a musical in motion picture history. The soundtrack to Dreamgirls, featuring Hudson's acclaimed version of "And I Am Telling You I'm Not Going," reached Number One on the Billboard Top 200 album chart on January 10, 2007, after five weeks in release. Hudson, who signed a recording contract with Clive Davis' Arista label in late 2006, is expected to release her debut album sometime in 2007.

Camile Velasco returned to the Philippines in December 2004 after 17 years for a whirlwind tour of television appearances and a concert with Martin Nievera. In 2005, she signed to Motown Records, but left the label after a lack of promotion for her first single. Camile performed at several concerts in Hawaii, California and Illinois, maintaining her ambition to become an artist. In 2006, she appeared in a Black Eyed Peas video and performed in Hawaii, California, Nevada, New Jersey, New York and the Philippines. Camile is now writing and producing her own songs on UHype Records.

Eleventh place contestant Matthew Rogers is now a TV personality, starring alongside Mikalah Gordon on American Idol Extra, which went behind the scenes of American Idol's fifth season.

In May 2005, Telescope announced that the third season had a total of approximately 360 million votes.

In Season 2, Seacrest surfaced as the lone host. Dunkleman reportedly hated working on the show and the studio was dissatisfied with his performance. Kristin Holt was a special correspondent. This time, Ruben Studdard emerged as the winner with Clay Aiken as a very close runner-up. Out of 24 million votes recorded, Studdard finished just 130,000 votes ahead of Aiken. The accuracy of the reported results is still disputed. There was much discussion in the communication industry about the phone system being overloaded, and that more than 150 million votes were dropped, making the voting suspect.[3] Since then, the voting methods have been modified to avoid this problem.

In an interview prior to the start of the fifth season, executive producer Nigel Lythgoe revealed for the first time that Aiken had led the fan voting from the wild card week onward until the finale.[4] Clay Aiken became the first American Idol non-winning contestant to have a U.S. Hot 100 number-one with "This Is the Night", written by British songwriter Chris Braide with Gary Burr and Aldo Nova. Studdard and Aiken both released albums in the fall of 2006. Kimberley Locke has also enjoyed radio success after American Idol with her debut album, One Love. Her second album, Based on a True Story, was released in May 2007.

Fourth-place finisher and former Marine Josh Gracin has had huge success as a country artist. His first album spawned three hit singles, including the number-one U.S. country song, "Nothing to Lose". He is signed with Lyric Street Records.

Sixth-place finisher Carmen Rasmusen signed with independent country record label Lofton Creek Records and her first single "Nothin' Like the Summer" is having a good rendition on American radios.

One contestant, Frenchie Davis, was disqualified and removed from the competition after topless photos of her surfaced on the Internet. She later appeared in the Broadway musical Rent.

During the course of the contest Studdard became known for wearing 205 Flava jerseys representing his area code. Shortly after the end of the contest, Studdard sued 205 Flava, Inc. for $2 million for using his image for promotional purposes. Flava responded by alleging that Studdard had accepted over $10,000 in return for wearing 205 shirts, and produced 8 cashed checks to validate their claim. The allegations, if true, indicate a clear violation of the American Idol rules.[5] The lawsuit was settled out of court.[6]

The rumor mills were buzzing once again in 2005 when Season 2 contestant Corey Clark, who the producers say was kicked off the show because of a police record he had not disclosed earlier, alleged that he had an affair with judge Paula Abdul during his time on the competition and that's the reason he was kicked off. Clark also alleged that Abdul gave him preferential treatment on the show because of their alleged romance. A subsequent investigation by an independent councel hired by Fox "could not corroborate the evidence or allegations provided by Mr. Clark or any witnesses".

The first season of American Idol debuted without hype as a summer replacement show (with the full title American Idol: The Search For A Superstar) in June 2002 on the Fox Broadcasting Company after being rejected by numerous other networks. The show's co-hosts were Ryan Seacrest and Brian Dunkleman. Through word of mouth generated by the appeal of its contestants and the presence of acid-tongued British judge Simon Cowell, the show grew into a phenomenon. An estimated fifty million people watched the Season 1 finale in September 2002. Following such a success, the second season was moved to air the upcoming January. The number of episodes increased, as did the show's budget and the charge for commercial spots.

Winner Kelly Clarkson signed with RCA Records, the label in partnership with American Idol's 19 Management. Immediately post-finale, Clarkson released two singles, most notably the coronation song "A Moment Like This" which climbed to number 52, but marked the biggest jump in Billboard Hot 100 history when it shot to number one, breaking a record set by The Beatles. As part of the promotion planned for the show's first winner, the song had been pre-recorded ready to air on radio stations the day after the finale. Appearances on numerous entertainment/news shows followed, as did videos for the singles that began airing on MTV's TRL. Clarkson has subsequently had three successful albums: Thankful, Breakaway, and "My December", and several hit singles mostly from her more successful second album Breakaway. While her first album failed to sell outside of North America, her second was a global success and garnered two Grammy Awards in 2006, the third album is right now on track, selling more than 1 million copies worldwide in two months, and has been certified Platinum in Canada.

The show inspired a 2003 musical film, From Justin to Kelly, featuring Kelly Clarkson and runner-up Justin Guarini. The musical love story, produced by American Idol's Simon Fuller, was filmed in Miami, Florida over a period of six weeks shortly after the season ended. Released several months later in June 2003, the film failed to make back its budget during its short run in theatres and is often ranked among the worst movies ever made. A DVD with additional footage was released and the movie airs periodically in the U.S. and other countries.

Besides Clarkson and Guarini, also signed were Nikki McKibbin (3rd), Tamyra Gray (4th), RJ Helton (5th), and Christina Christian (6th). It is the only year the runner-up did not release a single following the show's finale.

Runner-up Justin Guarini also signed with RCA Records. Contract restrictions required him to reject outside offers received and delay solo projects following the season finale, eventually debuting an album in 2003 after the conclusion of Season 2. RCA dropped him shortly after its debut. Guarini formed his own entertainment company and independently released a second album in 2005, with a third album and an independent movie scheduled for release in 2006. Nikki McKibbin signed with RCA, but quit because she refused to record a country album. She has since made appearances on various Reality TV shows and is working on her debut album. Tamyra Gray was signed to RCA but was dropped when she demanded to write the album. She then signed with Idol creator Simon Fuller's new label 19 Entertainment. Gray's self-written debut album was released in 2004. In 2005, she was dropped by the label. She had a supporting role in the 2005 movie The Gospel. RJ Helton released a Christian album, but sales were lackluster. Ryan Starr had trouble getting out of her contract with RCA Records but managed to independently release a single, My Religion, which sold 360,000 downloads via iTunes. She is expected to release her debut album in 2007. Jim Verraros, who came out of the closet after being voted in American Idol, starred in an indie film and released a dance-pop album, charting a dance hit on Billboard. Christina Christian, EJay Day (tenth), and AJ Gil (eighth) have had little success after the show.

Starting September 30, 2006, the first season of American Idol has been airing as "American Idol Rewind" and is syndicated on select T.V.D. stations in the US.