[1] In 1977, the 14-year-old Sjögren participated in the prestigious European Junior Championships, and won gold in both the singles and doubles tournaments, beating Christian Schultes in the final of the former.

[2] In the latter, he paired with fellow countryman Jörgen Windahl, and in the final, they beat Schultes and P. Ewaldsen of Germany.

[4] Shortly after he turned 16 in 1979, Sjögren started competing in the ITF Junior Circuit in the under-18 category, mainly as a doubles player.

In his first tournament, the 1979 Stockholm Open, he paired with fellow countryman Per Larsson, and lost in the first round to eventual runners-up Wojciech Fibak and Tom Okker.

Sjögren made the lineup as a freshman in the 1982–83 season and flourished, helping the team reach the national semi-finals of the NCAA Division II individual championships in both singles and doubles.

[1] For several years, Sjögren worked at the Danish Tennis Association, among other things as sports director, and got to see Caroline Wozniacki's journey up close, which eventually led her to become world's No.

[3] As the Head of Sport for the Swedish Tennis Association, a position he held for 7 years between 2009 and 2016,[3] Sjögren participated in a round table discussion on a coaching seminar during the 2014 ATP World Tour Finals event.