Born in Waxahachie, TX; educated at the University of Oklahoma, University of Colorado, Texas Christian University and the Actors Studio. While he was studying at with Sanford Meisner, he supported himself as a page at the NBC Studios in Rockefeller Plaza. His theatrical debut was in the Off-Broadway production of Viet-Rock, an anti-war play featuring music. He became part of avant-garde director Tom O'Horgan's stock company at La Mama, appearing in the infamous Futz, among other productions. He became a leading man in the 1970s and 80s, in several films by Francis Ford Coppola (THE CONVERSATION, 1974; APOCALYPSE NOW, 1979; ONE FROM THE HEART, 1982; TUCKER: THE MAN AND HIS DREAM, 1988); memorable in the title role of HAMMETT (1983), Wim Wenders's moody, cerebral essay in film noir. Other notable credits include THE ROSE (1979), "Right to Kill?" (1985, TV), "Lonesome Dove" (1989, TV mini-series, as "Blue Duck"), MUSIC BOX (1989), THE TWO JAKES (1990), "Citizen Cohn" (1992, TV as Dashiell Hammett), FALLING DOWN and TRAUMA (both 1993), LASSIE (1994), ONE NIGHT STAND (1995), THE BRAVE, THE END OF VIOLENCE and ONE OF OUR OWN (all 1997), IMPLICATED, BOOGIE BOY, WHATEVER, THE FIRST 9 ½ WEEKS, and POINT BLANK (all 1998), SHADOW HOURS, THE SPREADING GROUND, MILITIA and A PIECE OF EDEN (all 2000), THE HOUSE NEXT DOOR (2002), THE QUALITY OF LIGHT (2003), and ALL THE KING'S MEN (2006). Forrest was married to actress Marilu Henner from 1980 to 1983.  Nominated for Supporting Actor 1979: THE ROSE 1 nomination