Miller was born in 1959 and raised in a musical family that includes his father, William Miller (a church organist and choir director) and jazz pianist Wynton Kelly. By 13, Marcus was proficient on clarinet, piano and bass guitar, and already writing songs. Two years later he was working regularly in New York City, eventually playing bass and writing music for jazz flutist Bobbi Humphrey and keyboardist Lonnie Liston Smith. Miller soon became a top call session musician, gracing well over 500 albums, a short list of which includes Herbie Hancock, Mariah Carey, Wayne Shorter, McCoy Tyner, Frank Sinatra, Dr. John, Aretha Franklin, Elton John, Grover Washington Jr., Donald Fagen, Bill Withers, Chaka Khan, LL Cool J and Me'shell NdegéOcello and Flavio Sala.