Marcus was born in The Bronx, New York, United States.
[1] He studied at the Berklee College of Music in Boston, Massachusetts, between 1959 and 1961.
[1] He gained experience playing in the bands of Stan Kenton, Herbie Mann and Larry Coryell from 1963 to 1973.
[1] His first album as a leader included an arrangement of the Beatles' song, "Tomorrow Never Knows".
[2] With Gary Burton With Larry Coryell With Jazz Composer's Orchestra With Stan Kenton With Herbie Mann With Bob Thiele Collective With Young Rascals