Thomas Eagleton was born on 4 September 1929 in St. Louis, Missouri, USA. He was married to Barbara Ann Smith. He died on 4 March 2007 in Richmond Heights, Missouri, USA.
He was a first cousin, once removed, of British actor Dominic West. Thomas's paternal grandparents, Thomas Francis Eagleton and Mary Theresa Hennelly (who had moved to Missouri from Ireland), were also the paternal great-grandparents of West.
