Robert Koster was born to Henry Koster, a well-known Hollywood director whose film credits include The Bishop’s Wife (1947), My Blue Heaven (1950), and Harvey (1950). Koster attended UCLA where he studied film. Upon graduation, Koster joined the Directors Guild in 1962 as a Second AD and moved to New York, working on everything from commercials, documentaries and the occasional feature film, such as Valley of the Dolls (1967), Pendulum (1969), Generation (1969), and Hello, Dolly! (1969). While in New York Koster also worked as an AD on commercial sets for the J. Walter Thompson Advertising Agency and the sets of CBS television shows. In the early 1970s Koster moved back to Los Angeles where he continued his assistant director duties, as well as working as a UPM on several productions. Koster’s film credits include Bananas (1971), The Man in the Glass Booth (1975), Futureworld (1975), Butch and Sundance: The Early Days (1979), That Was Then…This is Now (1985), and Child’s Play 2 (1990). 

Koster also led an extensive career in television, working on the television movies Outrage (1973), Can Ellen Be Saved? (1974), Trilogy of Terror (1975), More Than Friends (1978), Space Force (1978), Dark Night of the Scarecrow (1981), Between the Darkness and the Dawn (1985), The Gladiator (1986), and War and Remembrance (1988), as well as the television series Quincy M.E., When the Whistle Blows, McClain’s Law, Trauma Center, Police Story, Fantasy Island, Code Name: Foxfire, and Supercarrier.