Hines ran 9.9 with a hand-clenched time at the U.S. Championships in Sacramento in the summer of 1968.
At the Mexico Olympics at high altitude in October of that year, he won the 100 meters in 9.95 and officially became the first person to run under 10 seconds with electronic timekeeping. After the Mexico City Olympics, Hines quit track and field at just 22 years old and switched to American football, NFL, where he had a brief unsuccessful career. He was also a member of the United States' winning 4x100 meter relay team.