From Wikipedia, the free encyclopedia. William Christopher (October 20, 1932 – December 31, 2016) was an American actor and comedian, best known for playing Private Lester Hummel on Gomer Pyle, U.S.M.C. from 1965 to 1968 and Father Mulcahy on the television series M*A*S*H from 1972 to 1983 and its spinoff After MASH from 1983 to 1985. Description above from the Wikipedia article William Christopher, licensed under CC-BY-SA, full list of contributors on Wikipedia.