Gerard John Schaefer Jr. was born on March 25, 1946, in Wisconsin. He was the first of three children for Gerard and Doris Schaefer, describing himself in later life as the "illegitimate" product of a "forced marriage." His father did well as a traveling salesman for Kimberly-Clark, soon moving the family to an affluent suburb of Atlanta, Georgia. There, young Gerard did well at Marist Academy, a Catholic parochial school.
While one observer called Schaefer's early life "idyllic," but Schaefer didn't feel that way. He recalled that his parents "never had a good relationship"; his father was "always critical," his mother "always on my back to do better." Gerard Sr. favored daughter Sara, which made his firstborn "want to be a girl." He also had thoughts of suicide. "I wanted to die," Schaefer told psychiatrists. "I couldn't please my father, so in playing games I always got killed." At age 12 he "discovered" women's panties and began to masturbate while wearing them. He also practiced masochistic bondage: "I'd tie myself up to a tree, struggle to get free, and I'd get excited sexually and do something to hurt myself." Soon, the violent images turned outward. "I would fantasize hurting other people," he said, "women in particular." Schaefer admitted that he had a large preoccupation with death, sometimes reaching the point where he "didn't know what was fact and what was fantasy."
The Schaefers moved to Fort Lauderdale, Florida in 1960, promptly joining the local yacht and country clubs. Gerard Jr. met his girlfriend, Cindy, at age 14 and saw her steadily for the next three years. They were lovers, but Cindy would only perform in scripted scenarios, demanding that Schaefer tear her clothes and "rape" her each time they had sex. When he balked at continuing the game, in 1964, Cindy dumped him. The same day, Schaefer went into the woods and played his bondage games again for the first time since leaving Georgia.
Yearbooks from St. Thomas Aquinas High School list Schaefer as a member of the football team in his sophomore and junior years, but no one remembers him playing or joining in any other group activity. Classmates recall him as a loner, labeled "weird" and "out of it." One noted that Schaefer "would practically stand on his head to see up a girl's skirt." In class, he angered the nuns by questioning religious dogma, once writing a long essay scientifically challenging the virgin birth of Christ.
Mostly, he preferred solitary pursuits, especially hunting in the Everglades. Neighbor Gary Hainline remembered that Schaefer "enjoyed shooting things you can't eat—songbirds, land crabs, that sort of thing." Schaefer sometimes played tennis with Gary's sister, Leigh, though sources disagree on whether they dated. Leigh Hainline was two years older than Schaefer, and he sometimes crept around her house at night, masturbating while he watched her undress. She was not the only female target of his voyeurism, but Schaefer blamed them all for "taunting" him, despising them as "sluts" and "whores."
In the spring of 1964, Schaefer met 17-year-old Sandy Steward at a school dance. She later described him as a "dazzling young stranger" who swept her away and became her first lover, all the while impressing her family with his impeccable manners. Schaefer took her on excursions to the Everglades, seeming amused when Sandy couldn't bring herself to kill an animal for sport. She found him "a sensitive and enthusiastic lover," eager to please. Schaefer graduated in June 1964 but the romance continued. He traveled with Sandy's family and became a fixture at their home. For the first time, his life seemed truly idyllic—but it was all a charade.