Stefan Nils Edwin Johansson was born on 8 September 1956 in Växjö, Sweden. He rose through British Formula Three — winning the 1980 championship with Ron Dennis's Project Four team — before establishing himself in Formula One across eleven seasons and ten different teams. His most productive F1 years came at Ferrari in 1985 and 1986, where he finished fifth in the Drivers' Championship in 1986, and at McLaren alongside Alain Prost in 1987, scoring five podiums on his way to sixth in the standings. After stints with Ligier, Onyx, AGS, and Footwork, Johansson departed Formula One following 1991 and turned toward American open-wheel competition.
Johansson made his CART debut in 1992 and immediately impressed, winning the Rookie of the Year award ahead of Belgian driver Eric Bachelart. He recorded two third-place finishes in that inaugural season, demonstrating the racecraft developed across a decade of Formula One.
In 1993, Johansson claimed his first CART pole position at Portland, though as had been the pattern throughout his career, a race victory remained elusive. His best overall season in the series came in 1994, when he finished eleventh in the championship standings.
He competed in the Indianapolis 500 across three consecutive years, entering the 1993, 1994, and 1995 editions of the famous oval race. These Indy 500 appearances formed a significant part of his broader campaign in American open-wheel racing during that period.
Johansson's CART tenure came to a tragic conclusion at the 1996 Molson Indy Toronto race. While racing, he was involved in a catastrophic accident that claimed the life of fellow driver Jeff Krosnoff and track marshal Gary Avrin. After making wheel-to-wheel contact, Krosnoff's car struck the barriers and then a lamp post positioned too close to the track, with Krosnoff dying instantly from injuries sustained in the impact. The accident at Toronto proved to be Johansson's final CART event; he retired from the series at the end of 1996 having started 73 races over five seasons.
Following his CART retirement, Johansson returned to sports car racing, a discipline he had participated in alongside his single-seater career. He achieved one of motorsport's most celebrated victories in 1997 when he won the 24 Hours of Le Mans driving a TWR-Porsche WSC-95 for Joest Racing, sharing with Michele Alboreto — his Ferrari F1 teammate from 1985 and 1986 — and a young Tom Kristensen in what became Kristensen's first of a record nine Le Mans victories. Johansson also won the 1997 12 Hours of Sebring in a Ferrari 333 SP alongside Andy Evans, Fermin Velez, and Yannick Dalmas.
In 1997, Johansson founded an Indy Lights team, running Fredrik Larsson and Jeff Ward. The team subsequently fielded Guy Smith and Luiz Garcia Jr. in 1998, and Scott Dixon alongside Ben Collins in 1999. In 2003, he returned to CART as a team owner, running American Spirit Team Johansson with Jimmy Vasser and Ryan Hunter-Reay as drivers. Hunter-Reay scored a rain-soaked victory in Australia, but the under-funded team folded at the end of that season.
Johansson's CART career reflected the same consistency without ultimate victory that had characterised his Formula One years. His record of twelve Formula One podiums without a win was a notable statistical curiosity at the time — equalled later by Nick Heidfeld and then broken at the 2011 Malaysian Grand Prix. The Toronto tragedy of 1996 cast a long shadow over his final season in the series. Beyond racing, Johansson developed interests in art and watch design, and managed the careers of several drivers including Scott Dixon, Felix Rosenqvist, and Romain Grosjean.