He appeared in 1974 in two productions for Italian television, Miklós Jancsó's historical drama "Roma rivoule Cesare" and in the series "Orlando furioso", based on Ludovico Ariosto's epic poem. In 1982 Keller starred with his wife Kristina St. Clair in the cult Jamaican production "Countryman", which was his last film. Keller was married to actress Kristina St. Clair from 1981 to 1987 and had a daughter named Serena Keller Undercofler, who also works in the film industry as music supervisor. His last years were spent with his family in his native homeland in Atlanta, Georgia. He died there on January 20, 1997 of liver cancer at age 52. Keller was exposed to hepatitis C during the production of "Hair", which is linked to liver cancer.