His world record time of 9.79 was a sensation, and seemed certain to make him the face of the Games.
He was - but for all the wrong reasons.
Three days later, news broke that Johnson had tested positive for the anabolic steroid stanozolol. He was stripped of his gold medal and world record.
It was the biggest doping scandal ever, and marked the end of an age of innocence - with sport forced to face up to the widespread use of performance-enhancing drugs.
The Seoul 100m final has subsequently been described as 'the dirtiest race of all time'. Of the top five finishers, only Calvin Smith of the USA, never failed a drugs test during his career.
The eventual gold medallist Carl Lewis was revealed to have tested positive for stimulants three times before the 1988 Games, but the US Olympic Committee accepted his claim of inadvertent use.
Johnson's coach later claimed he had been using steroids since 1981, and he lost his 1987 World Championship gold, along with a previous world record.
Instead, Johnson's name echoes through history as sport's most iconic cheat.