The American dominated the 200m and 400m sprints in the final decade of the 20th century, winning four gold medals in the Barcelona (1992), Atlanta (1996) and Sydney (2000) Games.
His tally could have been five as he was part of the 4x400m US relay team that crossed the line first in Sydney but was stripped of the title eight years later, after Antonio Pettigrew admitted doping.
Johnson, always a vehement voice against doping, returned his medal as he felt he had not won it legitimately.
He was nevertheless the only man to win 400m gold twice (1996, 2000) and also won a 4x400m relay gold in 1992 and a 200m gold in Atlanta four years later when he smashed his own world record (19.66) by more than three-tenths of a second with a scarcely believable 19.32sec in the final - the largest improvement in a 200m world record in history.
Usain Bolt has since lowered the mark, but Johnson's 400 metres world record of 43.18sec set in Seville in 1999 still stands to this day.