He won the 100 meters at the 1977 IAAF Athletics World Cup in Düsseldorf whilst representing the USA. He also anchored the 4x100 meters USA relay team to a new world record time of 38.03 seconds, alongside Bill Collins, Steve Riddick and Cliff Wiley – an event statistician Mark Butler for the IAAF puts in his top 10 men's World Cup moments. Williams also received a bronze medal as a member of the 4x100 meters USA relay team at the 1981 IAAF World Cup in Rome.