Born to a Jewish family,[1] Gruskoff started his career in the New York mailroom of the William Morris Agency, and then took a job with Creative Management Associates, where he represented Dennis Hopper, Peter Fonda, Robert Redford, Natalie Wood, Faye Dunaway, James Coburn, Steve McQueen, Peter Sellers, Al Ruddy, and Irwin Winkler.
[2] Although Ned Tanen of Universal Pictures asked him to set up and run an independent film division, he instead accepted a three picture production contract.
Working with Douglas Trumbull, Michael Cimino, Sam Shepard, and Steven Bochco, he independently developed three low budget scripts: The Last Movie, Silent Running, and Conquering Horse, a Sioux language script which never made it to film but was the precursor to Dances with Wolves.
[2] In 1999, he was hired by Nick Wechsler and Keith Addis to work for their production company, Industry Entertainment, as an in-house producer and mentor to their junior producers including Geyer Kosinski, David Seltzer, Margaret Riley, Rosalie Swedlin, Julia Chasman, Marc Evans, and David Carmel.
[3] Gruskoff won a Cesar Award for the film Quest for Fire.