Dennis was born in Birmingham, raised in Doncaster and attended the Don Valley High School. When he was fourteen he joined the Doncaster Youth Jazz Association, with whom he studied and performed for some years, before moving to London in 1987 and joining NYJO alongside his brother Winston.
After recording, performing and touring with a host of musicians and bands in jazz and pop, including Courtney Pine and Maceo Parker, Dennis set up his own jazz-funk band, Dee Roe.
In 2000 he formed Dennis Rollins’ BadBone and Co., a quintet which was launched at the Barbican in March of that year, specialising in funk-inflected jazz. Current band members are; Jay Phelps on trumpet, Johnny Heyes on guitars, Courtney Thomas on bass, Ross Stanley on keys and Jack Pollit on drums.
He also had a band – Boneyard – an ensemble formed in 2005 featuring ten trombones, sousaphone (or “sousabone”), and drums; this band performed a series of live gigs throughout the U.K. that summer as well as a performance on BBC Radio 3. Boneyard featured the British jazz trombonists Barnaby Dickinson, Matt Colman, Julian Hepple, Andy Derrick, Kevin Holborough, Harry Brown, and Lee Hallam, with Andy Grappy on sousaphone.