This actor has had a long career on stage and on the large and small screens, most recently on "L.A. Law" and "The West Wing". On the latter he played hard-working and dedicated Leo McGarry, chief of staff to President Bartlet (played by Martin Sheen). Like his character on the show, Spencer was a workaholic and recovered alcoholic who suffered a heart attack. On TV, post-infarction he resigned from his job but came back to run for vice president alongside Matt Santos (Jimmy Smits); in real life, the heart attack killed him. John Spencer died on December 16, 2005.
Spencer was an only child, born in 1946 to working class parents: his father was a truck driver, his mother a homemaker and occasional waitress. He grew up in New Jersey and was an avid gardener, often winning 4-H awards for his tomatoes. As a teenager he had a recurring role on the Patty Duke show as boyfriend to the English twin Cathy. He enrolled in the Professional Children's School in Manhattan when 16, where he was in classes with future stars like Liza Minnelli and violinist Pinchas Zukerman. He studied for a time at Fairleigh Dickenson University and then New York University, but dropped out to pursue a career on the stage. He won an Obie award in 1981 for an off-Broadway production of "Still Life", and had small roles in a number of movies, including "War Games", "Sea of Love", and "Black Rain".
Spencer's big break was a long time coming, but in 1990 it finally hit when he was cast as Harrison Ford's lawyer sidekick in the courtroom drama "Presumed Innocent". This led to him being cast as the streetwise lawyer Tommy Mullaney on the final four years of "L.A. Law". He was nominated five times for an Emmy Award for his performance on "The West Wing", and won once. Ove the past several years he has appeared in a number of films, including "The Rock", "The Negotiator", "Albino Alligator", "Lesser Prophets", and "Cold Heart".
He does not appear to have been married or had children, and none of the obituaries I have seen today mention a same-sex partner, though IMDb mentions a long-time girlfriend with whom he lived in 2000, actress and choreographer Patricia Mariano.