Marcus is a Motion Picture Executive in Charge of Music and Music Supervisor in Los Angeles, California. In 1992, he became Director of Music and Supervisor at Motion Picture Corp. of America (Columbia / Tristar) in Los Angeles. He was appointed Executive in Charge of Music at Orion Pictures in 1998.

Today Marcus operates Film Music Group, a Motion Picture Music Supervision, Soundtrack, and Production Company in Los Angeles, working with clients including Lionsgate, Universal, Sony Pictures, Entertainment, MGM Pictures, NBC, ABC, MTV, A&E, Comedy Central Networks, and Lucasfilm / Skywalker Sound. Marcus is based at three state of the art digital recording studios in Los Angeles, Redwood City / Silicon Valley, and in Auburn, CA. Marcus is also a BMI composer, song writer and a studio musician. His music publishers are MGM Pictures Music, Sony / ATV and Famous Music (Paramount).