Resnick was born in Chicago March 5, 1942. He was a 1959 graduate of Highland Park High School  in Highland Park, Illinois. He sold his first piece of writing in 1957, while still in high school.:27 He attended the University of Chicago from 1959 to 1961 and met his future wife, Carol L. Cain, there. The couple began dating in mid-December 1960 and were engaged by the end of the month.:27 They were married in 1961.
In the 1960s and early 1970s, Resnick wrote over 200 erotic adult novels under various pseudonyms and edited three men's magazines and seven tabloid newspapers. For over a decade he wrote a weekly column about horse racing and a monthly column about purebred collies, which he and his wife bred and showed. His wife was an uncredited collaborator on much of his science fiction and a co-author on two movie scripts they sold, based on his novels Santiago and The Widowmaker.:9 His daughter Laura Resnick is an award-winning science fiction and fantasy author.
Resnick lived in Cincinnati from 1976 until his death following a battle with cancer on January 9, 2020.