After graduating from a Pittsburgh High School, Glenn entered the College of William & Mary, where he majored in English. He joined the United States Marine Corps for three years, then worked for about seven months in 1963 as a news and sports reporter for the Kenosha News, in Kenosha, Wisconsin. He tried to become an author, but found he could not write dialogue that satisfied the readers. To learn the art of dialogue, he began taking acting classes.[citation needed]
In 1968, he joined The Actors Studio[4][5] 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.
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.[6] He portrayed Eugene van Wingerdt in a leading role in the thriller film The Barber.[7] Glenn acted in the 2011 film Sucker Punch as Wise Man.
He played the character Stick in Netflix's television series Daredevil and returned to the character in The Defenders[8] 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.
Personal life
He married Carol Schwartz in 1968 and upon their marriage, Glenn converted to Judaism, his wife's faith, from Catholicism.[9][2] They have two daughters.[9]