John Spencer (December 20, 1946 – December 16, 2005) was an American actor. He first gained recognition for his captivating performances on Broadway, particularly in The Great White Hope (1969). Spencer transitioned to film, showcasing his versatility in movies like The Rock (1996) and The Negotiator (1998). On television, Spencer had one of his first on-screen roles in The Patty Duke Show, and later became known as a main cast member on L.A. Law starting in its fifth season. His portrayal of White House Chief of Staff Leo McGarry on The West Wing (1999-2006) brought widespread acclaim, earning him five Emmy Award nominations, including a win in 2002. Spencer passed away on December 16, 2005, at the age of 58.