In 1980, he appeared as ex-convict Wes Hightower in Bridges' Urban Cowboy. After that he starred in the World War II horror film, The Keep (1983), and action films such as Wild Geese II (1985) opposite Laurence Olivier, Silverado (1985), The Challenge (1982) and drama films such as The Right Stuff (1983), TV film Countdown to Looking Glass (1984), The River (1984) and Off Limits (1988) as he alternately played good guys and bad guys during the 1980s. He returned to Broadway in Burn This in 1987. That same year he tried his hand at gangster movies when he starred as the real-life sheriff turned gunman Verne Miller in the movie Gangland: The Verne Miller Story which was given a theatrical release only in Finland and went straight to video in the U.S. In the beginning of the 1990s his career was at its peak as he appeared in several well-known and/or blockbuster films such as The Hunt for Red October (1990), The Silence of the Lambs (1991), Backdraft (1991) and The Player (1992). He played a vicious mob hitman in a critically acclaimed performance in Night of the Running Man (1995). Later he gravitated toward more challenging movie roles, such as in the Freudian farce Reckless (1995), tragicomedy Edie and Pen (1997) and Ken Loach's socio-political declaration Carla's Song. In the late '90s Glenn alternated between mainstream films (Courage Under Fire (1996), Absolute Power (1997), independent projects (Lesser Prophets (1997) and Larga distancia (1998), written by his daughter Dakota Glenn) and TV (Naked City: A Killer Christmas (1998). He was also cast in a supporting role in Training Day (2001). Glenn was cast in the FX drama Sons of Anarchy (2008) as Clay Morrow but he was replaced after an early pilot episode by Ron Perlman. He portrayed Eugene Van Wingerdt in a leading role, in the thriller film The Barber.