Kennedy began writing songs with his brother at the age of thirteen and started a band at his school in Rotherham, Dinnington High School, but he was interested in composing and studio work more than performing. He apprenticed as an audio engineer, and after collecting insurance for an automobile accident, he purchased equipment and began working as an engineer on a freelance basis, which eventually led to production work. The first major band that Kennedy was in was World Still Turns, a studio band in Sheffield, along with former gospel singer John Taylor and Tom Chester; they received huge interest from all the major record companies. His first success as a producer was the hit single "Independence", the title song of the 1993 album by Lulu, which led to projects with Pauline Henry, Dannii Minogue, Kenny Thomas, and Take That. Kennedy has contributed songs to a number of film soundtracks, including Spice World, Stepmom, , Racing Stripes, and Bridge to Terabithia. He was nominated with Bryan Adams for the Golden Globe Award for Best Original Song for "Never Gonna Break My Faith" from Bobby and the Satellite Award for Best Original Song for "Never Let Go" also co-written with Adams from The Guardian. Kennedy and Adams were also nominated for a Grammy Award for Never Gonna Break My Faith recorded by Aretha Franklin and Mary J. Blige, for the film Bobby. Kennedy won an Ivor Novello award for Picture of You by Boyzone. For the 2011 series of The X Factor UK, he is credited as Talent Development and appears in the rehearsal studio on several episodes. Following his first series of involvement in The X Factor, he has teamed up with the series' 5th placed Janet Devlin and 6th placed Craig Colton, to write songs with them. In 2011 Kennedy was planning a concert in Sheffield to raise funds for his One Song Foundation. The concert was to mark his 21 years in the music business. In 2012 Kennedy was given an Honorary doctorate by Sheffield Hallam University for his contribution to the region's music industry, and for his outstanding work for charities, including his own One Song Foundation. Kennedy is the co-owner of The Steelworks Recording Company and also Kennedy Publishing and Production.
