(written from a Production point of view)
Prior to his role on Star Trek, Glass made several appearances on the television series Perry Mason. He made his feature film debut with a small, uncredited appearance in the 1960 epic Spartacus. Other Star Trek alumni featured in this film include Jean Simmons, Peter Brocco, John Hoyt, Arthur Batanides, William Blackburn, Paul Lambert, Vic Perrin and Dick Crockett.
He made small appearances in a number of other films, including Captain Newman, M.D. (1963, with James Gregory and Paul Carr), Slither (1972, with Sally Kellerman), Deliverence (1972, with Ronny Cox), Winterhawk (1975, with Elisha Cook, Jr.), Harry and Walter Go to New York (1976, with Ted Cassidy), Damnation Alley (1977, with Paul Winfield), and The Rose (1979, with Jonathan Banks). He also appeared in a 1978 made-for-TV movie called The Other Side of Hell, starring Morgan Woodward and featuring Richard Riehle, and in a 1979 TV movie called She's Dressed to Kill, featuring John Rubinstein and Jonathan Banks.