The 84-year-old had battled lung cancer for a year and a half before passing away with his wife at his side in his Pasadena home.
Co-star Loretta Swit (Major Margaret Houlihan) beautifully eulogized the actor to The Hollywood Reporter, saying: "Our Dear Bill and his goodness are a great argument for there being a heaven. I never heard him complain or lose his temper. Everyone adored him. A great sense of humor and a great humanitarian. He became TV's quintessential padre as Father Mulcahy on M*A*S*H. It was the most perfect casting ever known. He was probably responsible for more people coming back to the church. If God is nigh, then surely he or she will welcome Bill with open arms."
Christopher is survived by his wife and two sons, John and Ned.