Carlsson won 1984 junior tournament the French Open. Here he defeated, among others, Cyril Suk, Robbie White and Luke Jensen, as well as in the final Mark Kratzmann. He won in his career nine individual tournaments, including the biggest success in 1988 the title at the International German Tennis Championships at the Hamburger Rothbaum. Its highest ranking in the tennis world ranking was 6th place in the same year.
His best individual result at a Grand Slam tournament was the two-time reaching the second round of the French Open. In the doubles competition, he reached the second round of the U.S. Open.
Carlsson played between 1986 and 1988 four individual lots for the Swedish Davis Cup team that he could all win. He won it over Miloslav Mečíř, Henri Leconte and twice on Thierry Tulasne. In the final defeat of the World Group in 1988 he was the last single match are used, since Germany at that time had already won the Davis Cup, the match against Patrik Kuhnen was not played.