During the inaugural, 1973 World Aquatics Championships in Belgrade, Bottom took silver in the 100-meter butterfly and gold in both the 4×100-meter freestyle and 4×100-meter medley relay events. At the 1978 World Championships in Berlin he took gold in the 100-meter butterfly as well as the 4×100-meter medley relay. He won nine U.S. national championships between 1974 and 1980.