Gruenberg started his career in distribution at Warner Bros., moving to Columbia Pictures as senior VP and assistant sales manager, working on such films as Ghostbusters, Karate Kid and Silverado.
He then moved to MGM, serving as executive VP from 1991 to 1998. During that time, he managed the releases of Get Shorty, Tomorrow Never Dies, Leaving Las Vegas and Birdcage.
He became president of distribution at Miramax in 1998, where he oversaw the distribution of the Oscar- winning and box office hits Shakespeare in Love and Life is Beautiful.
He later joined First Look Studios as executive VP of distribution in 2005. There, he released The Proposition and Paris, Je t’aime, and Millennium Entertainment, where he successfully executed the release of Richard Linklater’s indie sensation,