Langan was born in 1952 in San Francisco, California. His mother, Mary Langan-Hansen ("née" Chappelle, 1932–2014), was the daughter of a wealthy shipping executive but was cut off from her family. Langan's biological father left before he was born, and is said to have died in Mexico. Langan's mother married three more times, and had a son by each husband. Her second husband was murdered, and her third died by suicide. Langan grew up with the fourth husband Jack Langan, who has been described as a "failed journalist" who went on drinking sprees and disappeared from the house, locked the kitchen cabinets so the four boys couldn't get to the food in them and used a bullwhip as a disciplinary measure. The family was very poor; Langan recalls that they all had only one set of clothes each. The family moved around, living for a while in a teepee on an Indian reservation, then later in Virginia City, Nevada. When the children were in grade school, the family moved to Bozeman, Montana, where Langan spent most of his childhood.