Harrison was born on July 13, 1942 at the Swedish Covenant Hospital, in Chicago, Illinois. He was the first child of Dorothy Nidelman and Christopher Ford.
After graduate from Maine Township High School in Park Ridge, Illinois, in 1960, he attended Ripon College in Wisconsin, and became a member of Sigma Nu fraternity. He took a drama class in his junior year chiefly, the first step to become an actor.

Somehow, he became fascinated with acting ("failed in all other fields" he claimed years later) and appeared as Mac the Knife in the musical play "The Threepenny Opera". While in college, toward the end of his freshman year, he was a member of a folk band called "The Brothers Gross." Finally, after failing a philosophy class in his senior year, he was expelled three days before graduation.