Hip-hop club DJ in the early '80s, as well as a musician. His name refers to Delancey Street, which is in a particularly multicultural area of Manhattan's Lower East Side. He later changed his name to Grandmixer DXT.

D.ST’s original group was The Infinity Four MC’s consisting of Kingpin Shahiem, Mike Nice, Baron and Legendary female rapper Kimba.
While working with The Infinity Rappers n 1982, he was part of the first hip hop tour to Europe with Afrika Bambaataa, Rammellzee, Fab 5 Freddy, Rock Steady Crew, the Double Dutch Girls, and graffiti artists Phase 2, Futura, and Dondi. He also appeared in the movie Wild Style with Rammellzee and Shock Dell at the Amphitheatre. His hands were controlling the scratching on Rockit track by Herbie Hancock. This song won a Grammy Award for Best R&B Instrumental Performance, which made GrandMixer D.ST the first DJ to win a Grammy.

Some sources give his real name as Derek Howells, but credits on releases list him as Derek Showard.