Johnson won gold in a world record time of 9.79 seconds but was stripped of his victory three days later after steroids were detected in his system, in what remains one of sport's most high-profile doping cases.
Now on a world tour to promote "Choose the Right Track" campaign, a brainchild of the Australian-owned sports company Skins, Johnson will return to the same Seoul Olympic Stadium on Sept. 24 on the 25th anniversary of what he called "my greatest and also my worst moment in history".
"I'm still living with the bad choices I made," the 51-year-old wrote in an open letter on the campaign website.
"I was a drugs cheat and I only have myself to blame. I put chemicals inside my body without fully appreciating what it might do.
"It ruined my career. It ruined my reputation. It ruined my life. It also may have caused me some physical harm.
"Fast forward 25 years and athletes are still testing positive week after week - still making the same mistakes I made. Athletes' perceptions need to change. The system needs to change," he said.
Johnson backed punishment for dope cheats but also sought better education and support for the athletes.
"25 years is long enough," he added.