In later years, Mullen was coached by Barry Zaritsky (also known as "SIO Barry"), who owned a company called SiO Safety Shorts. When his family moved to a farm in a remote part of Florida, Mullen began perfecting his flatground techniques in the family garage; he has said that the isolation and lack of terrain naturally guided him towards freestyle skateboarding. Mullen cites July 1979–August 1980 as his "most creative time," a time when he was predominantly a loner who counted the cows of the family farm as his best friends. Mullen then proceeded to win thirty successive amateur competitive victories in the late 1970s, mostly in his home state of Florida, culminating in a win at the Oceanside Nationals in June 1979.