After the breakup of his first marriage and the dissolution of his business, Arbus decided to leave photography behind and pursue a new career in acting. In 1969 he moved to California. His new career took off after he landed the lead role in Robert Downey Sr.'s cult film "Greaser's Palace" (1972), in which he appears with Robert Downey, Jr. (who would go on to star as Diane Arbus's muse in "Fur", a fictional account of the end of the Arbuses' marriage). Arbus also starred opposite Bette Davis in "Scream, Pretty Peggy" in 1973, and was featured as Gregory LaCava in "W.C. Fields and Me" in 1976. These roles led to his casting as Maj. Sidney Freedman on "M*A*S*H", although in an early episode, "Radar's Report" (1973), he was called "Milton Freedman".