In December 1989, he transferred to English team Chelsea, where he played for eight seasons and was voted player of the year for the club in 1995.
[6] Shortly after this he returned to his native Norway where he played for Rosenborg and finally Strømsgodset before retiring in June 1999.
Johnsen was a central defender who was capped 19 times for the Norwegian national team, participating in the 1994 World Cup.
He also won five caps during Norway's unsuccessful qualification campaign for 1988 Olympics, although these are not recognized as full internationals by FIFA.
Perhaps the most famous moment in Johnsen's career came on 15 November 1989, during a match between Norway and Scotland, at Hampden Park, where he scored a goal from the middle of the pitch.
Legendary Scottish goalkeeper Jim Leighton said about the shot twenty years later: "I'm never allowed to forget about it in Scotland, it is the furthest I've ever lost a goal from."