Kara Dioguardi
While her early solo and band efforts did not result in commercial successes, she became a highly sought-after songwriter, writing or co-writing many international hit songs from 1999 to today (see discographies and awards below). To date, she has had 39 albums in the Top 10 on Billboard's 200 album chart. Her songs are on over 100 million records. The majority of her songs have been recorded by American females in the pop/rock genre, with a significant minority of songs recorded by Australian females, and Latin music artists. DioGuardi can be heard performing backup vocals on some of these recordings.

DioGuardi also helped write the song "Not Meant To Be" with Tyler Connolly which appears on Theory of a Deadman's 2008 album Scars & Souvenirs. She is also featured as the love interest in the music video which was released on March 10, 2009. This was her debut in the music video industry.

In 2009, she co-wrote a song called Temporary with Nick Lachey and producer Mitch Allan for Nick's upcoming CD, Coming Up for Air; the two recorded it as a duet.

DioGuardi co-owns Arthouse Entertainment, a publishing company that is a resource business for record companies and other music entities seeking compositions, productions, artists, and related music services. Arthouse has been a part of many chart-topping hits including Cassie's "Me & U" (written and produced by Ryan Leslie), Jim Jones' "We Fly High" (written and produced by Zukhan Bey), Nick Lachey's "What's Left of Me", David Archuleta's single "Crush" (written and produced by Eman Kiriakou), Mika's "Grace Kelly" and also OneRepublic's "Apologize" and "Stop and Stare" (all produced by Greg Wells), Faith Hill's "Lost" (written and produced by Kara DioGuardi and Mitch Allan), Sober by P!nk and "Pieces of Me" by Ashlee Simpson.

In July 2006, DioGuardi was a judge in an "Idol"-like TV show called The One: Making a Music Star. The show debuted on ABC with the second-lowest rating ever for a premiere on a major American network and was abruptly canceled after just two weeks.

She joined the hit Fox television show American Idol as a fourth Judge starting in the show's eighth season (January 13, 2009). She has had Idol connections in the past: in 2000, DioGuardi and fellow Idol judge Paula Abdul co-wrote the UK number-one single "Spinning Around", performed by Kylie Minogue. She has written many songs sung by Idol winners and alumni such as Kelly Clarkson, David Archuleta, David Cook, Carrie Underwood, Diana DeGarmo, and Katharine McPhee