Glenn made his
Broadway debut in
The Impossible Years in 1965. He joined
George Morrison’s acting class, helping direct student plays to pay for his studies and appearing onstage in
La MaMa Experimental Theatre Club productions. In 1968, he joined
The Actors Studio and began working in professional theatre and TV. Two of Glenn's early television roles were as Hal Currin in the 1966 crime series
Hawk, starring
Burt Reynolds, and Calvin Brenner on the CBS daytime serial
The Edge of Night. In 1970, director
James Bridges offered him his first movie role, in
The Baby Maker, released the same year. Glenn spent eight years in
Los Angeles, California, acting in small roles in films and doing TV stints, including a TV movie
Gargoyles. In 1978, Glenn left
Los Angeles with his family for
Ketchum, Idaho, and worked as a barman, huntsman, and mountain ranger, occasionally acting in
Seattle stage productions. He appeared in
Francis Ford Coppola's
Apocalypse Now (1979) and worked with directors such as
Jonathan Demme and
Robert Altman. 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), and
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, Glenn's career was at its peak as he appeared in several well-known 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 & Pen (1997), and
Ken Loach's sociopolitical declaration ''
Carla's Song. In the late 1990s, 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
. Glenn acted in the 2011 film Sucker Punch'' as Wise Man. Glenn appeared in the drama
Freedom Writers, in which he played the father of
Hilary Swank's character, and in
The Bourne Ultimatum and
The Bourne Legacy as CIA Director Ezra Kramer. He played the character
Stick in Netflix's television series
Daredevil and returned to the character in
The Defenders series a year later. In 2020, he played the grandfather in
Greenland, opposite Gerard Butler & Morena Baccarin—an apocalyptic thriller about a comet destroying most of Earth. In 2024, he joined the cast of season 3 of the
HBO series
The White Lotus as Jim Hollinger, co-owner of the Thailand White Lotus resort. In September 2025,
Oldenburg International Film Festival paid tribute to Glenn with a retrospective of his career. The festival opened with the world premiere of
Eugene the Marine, a film directed by
Hank Bedford. The movie stars Glenn in the lead role of Eugene Lee Grady, a former marine struggling to keep his life together as his son is trying to force him out of his longtime home as a series of murders occur targeting the people around him. ==Personal life==