John Spencer, an Actor's Actor The actor died on Dec. 16, 2005, at age 58. We replay an interview from April 2000. Spencer is best known for his character Leo McGarry, the president's chief of staff, on the popular NBC series The West Wing. Spencer's and McGarry's lives ran parallel: Both were recovering alcoholics and both had driven personalities. McGarry suffered a heart attack on the show, and Spencer died of a heart attack. Spencer was previously a regular on L.A. Law and a veteran of many stage productions.