Jimmie Johnson began racing small motorcycles on dirt tracks at age five. By 2002 he’d made it to NASCAR’s elite Sprint Cup Series, where he eventually won six championships (putting him just behind Richard Petty and Dale Earnhardt, who won seven each). Off the track Johnson, now 40, competes in half-marathons and triathlons.
A version of this article appeared in the September 2016 issue (p.124) of Harvard Business Review.