Bunker was born "on New Year's Eve, 1933" into a troubled family in Los Angeles. His mother, Sarah (née Johnston), was a chorus girl from Vancouver, and his father, Edward N. Bunker, a stage hand. His first clear memories were of his alcoholic parents screaming at each other, and police arriving to "keep the peace." When they divorced, Bunker ended up in a foster home at the age of five, but he felt profoundly unhappy and ran away. As a result, Bunker went through a progression of increasingly draconian institutions. Consistently rebellious and defiant, young Bunker was subjected to a harsh regime of discipline. He attended a military school for a few months, where he began stealing and eventually ran away again, ending up in a hobo camp 400 miles away. While Bunker was eventually apprehended by the authorities, this established a pattern he would follow throughout his formative years.