Roger Johansson began playing hockey with IF Troja-Ljungby in 1983, while from 1986-89 he played with Färjestad BK and won a Swedish title with them in 1988. Johansson was drafted by the Calgary Flames of the NHL in 1985 and joined the team in 1989, but played only 73 games during the next two seasons with them, before returning to Europe. From 1991-92, Johansson played with Leksands IF, but returned to the NHL in 1992-93, playing another 77 games for the Flames. In 1993, Johansson again moved back to Europe, resuming his play with Leksands, but he made his third appearance in the NHL in 1995, when he played 11 games with the Chicago Blackhawks. After his third unsuccessful stay in North America, Johansson finished his career playing with Färjestad from 1995-01. He won Swedish titles with them in 1997 and 1998.
Internationally Johansson played at the 1994 Olympic Winter Games, 1994, 1996 and 1997 World Championships and 1996 World Cup. He won an Olympic gold in 1994, World Championships silver in 1997 and bronze in 1994. After finishing his sporting career, Johansson founded his own hockey school named Ragges Hockeyskola.