Zac Zorn won his only major individual title when he took the 1968 NCAA 100 m freestyle for UCLA after winning silver in that event at the 1967 Pan American Games. He went to the 1968 Olympics as the world record holder in that event, but poor pace judgment ruined his chances for a medal and he finished eighth, and last, in the final. Zorn set one individual world record in 100 metres freestyle at the US Olympic Trials in 1968 and was a member of three world record breaking 4×100 metre freestyle relay teams - at the 1967 Summer Universiade in Tokyo with Ken Walsh and the non-Olympians Don Havens and Greg Charlton, at the 1968 US Olympic Trials in Long Beach with Steve Rerych, Ken Walsh, and Don Schollander, and at the 1968 Olympics.