The William Morris Endeavor board member passed away on Thursday (21Aug14), according to Billboard.com.
Grosslight began his career in 1974, when he founded Regency Artists. He joined the William Morris Agency in 1992 when it acquired Triad Artists.
Throughout his career, Grosslight worked with several musicians including Charlotte Church, the Eagles, Journey, Luis Miguel, Brian Setzer and Carly Simon.
He also organised Tv music specials with Tina Turner and Bruce Willis and secured the American rights for the Prince's Trust Concerts and Nelson Mandela's birthday show.
A joint statement from WME CEOs Ari Emanuel and Patrick Whitesell reads: "Peter was a true gentleman, whose generosity and unique sense of humor will be deeply missed.
"He was a pioneer in our industry and represented some of the greatest performers of our time. In addition to being a tremendous agent, he served as a valuable mentor to many of us. It was a privilege to work with him."