He became artistic director of the Group Repertory Theater in North Hollywood in 1973. He oversaw more than 350 productions during his tenure. The theatre was later renamed the Lonny Chapman Group Repertory Theater.
Mr. Chapman, a Tulsa native, began his career as an actor in the Chicago company of Mr. Roberts. He made his Broadway debut in the short-lived The Closing Door in 1949. The next year, he was cast as the athlete Turk in William Inge's Come Back, Little Sheba, which proved a hit. He later became friends with the playwright. In the 1950s, he became somewhat known as an interpreter of the works of Horton Foote, appearing in two of his plays, The Chase and The Traveling Lady, in which he played opposite Kim Stanley. During this time he also acted in Whistler's Grandmother and The Ladies of the Corridor, the latter a rare play by Dorothy Parker. Other Broadway credits include General Seeger and Marathon '33.
He appeared in countless television shows, including "McCloud," which starred his lifelong friend Dennis Weaver. (Weaver had been his understudy in Come Back, Little Sheba.
A memorial service will be held at noon Dec. 2 at the Lonny Chapman Group Repertory Theater, 10900 Burbank Blvd., North Hollywood.
He is survived by his wife, Erma, and a son.