Born and raised in Newark, New Jersey, David Marciano attended Northeastern University in Boston with an intention of becoming a biomedical engineer. After one, less-than-stellar year however, he decided to pursue other career options. An aptitude test narrowed the field to architecture or acting. He chose acting.

Beginning in June of 1983, Marciano spent a year working as an actor in Boston. During that time, he also attended bartender school and worked as a bartender. He appeared in little-theater productions, one local movie, and a commercial for Northeastern University, but he realized he needed more training.

Fortunately, he was accepted into the Drama Studio of London at Berkeley, California. Completing the one year course, he tried finding work as an actor in New York for a time; then in December, 1985, moved to Los Angeles. After working in commercials, he got his first major break: the guest star lead in an episode of Wiseguy.

Other guest star roles followed in such series as Duet, China Beach and Vietnam War Story. His film credits include Come See the Paradise, Harlem Nights and Lethal Weapon II.