Tillman was born in Milwaukee, Wisconsin. His father, George Tillman, worked at the American Motors plant in Kenosha, Wisconsin, and his mother was a secretary. Throughout his early childhood, Tillman would borrow his father's 8mm camera and would start to shoot things with Milwaukee's Public-access television cable TV channel. By age eight, Tillman got his hands on his very first television script, "All My Children", and wrote his first soap opera as well as his first five-minute show. Tillman recalled, years later, to an interviewer in regard to receiving the "All My Children"'s script," I told them about a certain plot change that I wanted and I thought I could help the characters out…That was the beginning for me, the writing."