Haddon launched his solo career as a Christian R&B vocalist with the Lost & Found on Tyscot/Verity in 2002. The set peaked at No. 1 on Billboard's Top Gospel Charts and received wide critical acclaim and spawned the hit "Sinner's Prayer" which was played extensively on gospel and mainstream R&B radio stations.
The 1970s-leaning Crossroads followed in 2004, led off by the upbeat single "God is Good". In an uncharacteristic move for marketing a gospel album, Haddon made an appearance on the long-running syndicated series Soul Train performing the single and the title track from the album.
Haddon appeared to be pushing his Gospel artistry further into the ranks of mainstream venues with 7 Days, released October 10, 2006. 7 Days was produced almost entirely by R&B producers Tim & Bob Balancing out the contemporary bulk of the album is the traditional gospel-flavored lead single "Heaven Knows" which Haddon produced himself.
Haddon and his brother Gerald also produced the comeback album Brand New Day for veteran gospel vocalist Vanessa Bell Armstrong. Deitrick Haddon & Voices of Unity's Live the Life won Gospel Music Workshop of America Excellence Awards for "New Artist of the Year - Urban Contemporary" and "Album of the Year - Urban Contemporary".
On September 2, 2008, Haddon released an album called Revealed. This album includes the popular single, "Love Him Like I Do" (featuring Mary Mary and Ruben Studdard). On July 27, 2010 Haddon made his film debut in a movie released directly to DVD called Blessed and Cursed.
On January 25, 2012, Haddon released Church on the Moon, his fifth album with Verity Records. The album debuted at No. 1 on the Billboards Top Gospel charts and No. 65 on the Billboard 200.
Haddon is part of the cast of the reality television show Preachers of L.A., which chronicles the lives of six Los Angeles preachers, including Haddon. The show began airing on October 9, 2013 and airs on the Oxygen network in the United States.