Robert Moss began his career as a stage manager. He worked on such Off-Broadway productions as A COUNTRY SCANDAL (1960), AS ALL IN LOVE (1961), THE PINTER PLAYS (1962), MAN AND SUPERMAN (1964), WAR AND PEACE (1965), and JUDITH (1965). In 1971, he founded Playwrights Horizons and ran it for ten years. Playwrights Horizons is a writers’ theater dedicated to the support and development of contemporary American playwrights, composers, and lyricists, and to the production of their new work. While he was in charge of Playwrights Horizons, the company produced many Off-Broadway shows, including: DEMONS: A POSSESSION (1974),COWBOY PICTURES (1974), THE CORONER’S PLOT (1975), THE LYMORTH MILLIONS (1975), VANITIES (1976), THE BOSS (1976), ANGEL CITY (1977), HOOTERS (1978), THREE SONS (1978), THE VIENNA NOTES(1979), IN TROUSERS (1979), and MARCH OF THE FALSETTOS (1981). He is credited with helping to develop Theatre Row and served on the board of the Off-Off-Broadway Alliance for five years.

In 1982, Moss became the Artistic Director of the Hangar Theatre in Ithaca, NY. He ran the company until 1996, when he became the Producing Artistic Director of Syracuse Stage. He stepped down from that position in 2007 but continues to teach at the Hollins Playwrights Lab in Roanoke, Virginia, as well as at Ithaca College, the Syracuse Drama Department, and Nazareth College. He has also taught courses for the undergraduate directing program at Playwrights Horizons Theatre School (affiliated with NYU). Moss has been on the board of the Stage Directors and Choreographers Foundation, Theatre Communications Group, and the Drama League Directors Project.