Gleason did not set out to be an actor growing up in Hudson County, NJ. Excelling in sports, he won a football scholarship to college. After graduation, Gleason played in minor league baseball for both the Cleveland Indians and Boston Red Sox farm teams. He drifted into acting in the mid-1960s, settling in NYC to study with Lee Strasberg at the famed Actors Studio. He became involved in the growing off-Broadway theater scene as a writer, director and actor, working with such prestigious companies as Cafe LaMama and the Ensemble Studio Theatre. Gleason made his Broadway debut supporting Maureen Stapleton in Neil Simon's "The Gingerbread Lady" (1971). He went on to appear in both the L.A. and NYC revival of "The Front Page" (1972) with John Lithgow and Richard Thomas and won praise for his McMurphy in the off-Broadway revival of "One Flew Over the Cuckoo's Nest" (1973).
Gleason segued into TV work with numerous guest appearances ("Love American Style", "Adam-12", "Mission: Impossible", etc.) before landing the role of David Thornton in the ABC daytime drama "All My Children" (1975-78). Dr. Thornton was a quintessential Gleason character--hot headed, but principled. He made his TV miniseries debut with Robert Duvall and Lee Remick in "Ike" (ABC, 1979). He continued to appear in TV-movies, generally as a cop (e.g., "Fourth Story" on Showtime in 1991, the short-lived CBS series "One West Waikiki" in 1994) or academic leaders (e.g., "Spooner" for the Disney Channel in 1989, "Revenge of the Nerds IV; Nerd in Love" on Fox in 1994).
Gleason had supporting roles in such films as "Arthur" and "The Pursuit of D.B. Cooper" (both 1981) and "Tender Mercies" (1982) before his villainous turn in "Trading Places". Similar white collar adversaries and bad guy roles followed in "Morgan Stewart's Coming Home" (1987) and "Die Hard" (1988). In the 90s, he has continued to play supporting roles in films like "Miami Blues" (1990), Boiling Point" (1993) and "Digital Man" (1995).