The family always parked their caravan at Hemmeslöv's campsite early in the summer and that is where Kent started to play tennis at the age of four.

[1] As a result of Björn Borg's huge success at the top level, everyone in the neighborhood wanted to play tennis.

[1] His successes at Båstad were of great importance to Carlsson since they encouraged him to pursue a tennis career despite not being "born with an athletic body".

[1] For instance, Carlsson was diagnosed with "grasshopper knee bowl" in 1983, by Dr Jan Ekstrand, who had previously worked with, among other groups, the Sweden national team.

[1] Carlsson believed that with his medical issues his only chance to reach the top level would be to take shortcuts and play at a quicker pace.

[1] In the following season, he won the Roland Garros Boys' Singles title in 1984 without losing a set, defeating Mark Kratzmann in the final.

[9] After losing to Mats Wilander at Barcelona of October 1984, Carlsson did not play his first tournament until April 1985 in Bari, where he lost to Emilio Sánchez.

Starting the 1986 season in April, Carlsson won his first title on the ATP in Bari by defeating Horacio de la Peña.

[11] In addition to the two titles, Carlsson made two finals at Boston and Indianapolis which was played on green clay losing to countryman Mats Wilander both times.

Carlsson won both his singles matches for Sweden against France in the Davis Cup quarter finals at Fréjus defeating Thierry Tulasne 6–1, 3–6, 6–1, 6–2 and Henri Leconte 7–5, 6–2, 7–5.

[13] After retirement from the professional tour, Carlsson trained Magnus Norman, Thomas Johansson, Nicklas Kroon, and Aki Rahunen.

He developed the interest as a teenager and it was natural for him to take this as a new career and said "there is a great deal of satisfaction from training a horse from the beginning".