Dave was born in Oakland, California, in 1952. There was a half-size violin kept in the closet in case he wanted to be a concert violinist. He played trumpet at the age of nine, moving to baritone horn at the age of eleven, followed by a stint on drums until settling on electric bass at thirteen, adding upright bass to the mix until the switch to saxophone at the age of twenty-one. He has specialized in the baritone saxophone since the early seventies. 
 Sewelson arrived in New York City in the summer of 1977, settled in the East Village becoming a stalwart of the downtown scene, played in many bands of the area including the 25 O’Clock Band, Jemeel Moondoc’s Jus Grew Orchestra, Saheb Sarbib’s Multinational Big Band ,Noise R Us, Mofungo, Freedomland and Fast ‘n Bulbous. He was a founding member of the Microscopic Septet. Lifetime member of William Parker’s Little Huey Creative Music Orchestra. He has played with many wonderful musicians, including, Billy Bang, Peter Kuhn, Alex Cline, Roy Campbell, Sonny Murray, Kidd Jordan, Will Connell and Stephanie Stone. Current projects include, Two Sisters Inc., Sewelsonics, the MFAFWQ, Trio Dave, and Orchestra Dave and the Jesse Dulman Quartet.