Kevin Conway, a veteran actor known for his work in Gettysburg, Thirteen Days and Invincible, among others, died Wednesday of a heart attack, his publicist told Deadline. He was 77.

New York City-born Conway worked as an IBM sales analyst before becoming an actor at age 24. He went on to a decades-long career with dozens of credits in film, television and on the stage. His first major screen role was playing Roland Weary in the 1972 film Slaughterhouse Five, based on the Kurt Vonnegut novel. He went on to play Crum Petree, the insane mailman in the 1988 film Funny Farm; Frank Papale in the 2006 Disney football drama Invincible; and General Curtis LeMay in the 2000 historical drama Thirteen Days. He also played the fictional Sgt. Buster Kilrain in Ron Maxwell’s 1993 epic Gettysburg (see photo above) and its 2003 follow-up Gods and Generals.

His television work included playing Roger Chillingworth in a 1979 TV production of The Scarlet Letter, a role later played by Robert Duvall in 1995’s The Scarlet Letter. Conway also had a memorable guest-starring role on NBC’s Homicide: Life on the Street. In the 1995 episode titled “Heartbeat,” he played Joseph Cardero, the prime suspect in a cold-case murder who is obsessed with Edgar Allan Poe. Cardero ultimately meets his end in the same manner his victim did – and with a chilling nod to Poe’s The Tell-Tale Heart.

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Conway’s stage credits include a 1974 Drama Desk-winning Off Broadway performance in When You Comin’ Back, Red Ryder? and a 1970 Broadway debut in the play Indians starring Stacy Keach and Raul Julia. In 1975 he played George opposite James Earl Jones’ Lennie in Of Mice and Men, and in 1979 starred opposite Philip Anglim in the acclaimed The Elephant Man. His last Broadway credit was 2002’s Dinner at Eight opposite Joanne Camp, John Dossett, Marian Seldes and Christine Ebersole.

As a director, Conway helmed the 1987 independent film The Sun and the Moon.

His numerous other TV credits include the Control Voice for The Outer Limits revival series from 1995-2002. He guest-starred on Star Trek: The Next Generation as the clone of the legendary Klingon figure Kahless, as well as on The Good Wife, JAG, Law & Order, In the Heat of the Night and The Black Donnellys. Conway also recurred on HBO’s prison drama Oz as Seamus O’Reilly, the abusive father of Irish gang inmates Ryan and Cyril O’Reilly.

Erik Pedersen and Greg Evans contributed to this story.