From Wikipedia, the free encyclopedia. Thomas Mitchell (July 11, 1892 – December 17, 1962) was an American actor, playwright and screenwriter. Among his most famous roles in a long career are those of Gerald OHara, the father of Scarlett OHara in Gone with the Wind, the drunken Doc Boone in John Fords Stagecoach, and Uncle Billy in Its a Wonderful Life. Mitchell was the first person to win an Oscar, an Emmy, and a Tony Award. Description above from the Wikipedia article Thomas Mitchell, licensed under CC-BY-SA, full list of contributors on Wikipedia.