His best result in the mixed was making the quarter-finals of the 2002 Wimbledon Championships, partnering countrywoman Åsa Svensson.

In the men's doubles he twice reached the third round, the first time being his Grand Slam debut, at the 2000 Australian Open.

Landsberg and his partner Simon Aspelin defeated the number six seeds in that tournament, South Africans David Adams and John-Laffnie de Jager.

His other men's doubles partners at Grand Slam level were Stephen Huss, Thomas Johansson, Aleksandar Kitinov, Jarkko Nieminen Peter Nyborg, Robin Söderling and Jeff Tarango.

He made his final ATP World Tour appearance in the 2007 Swedish Open and now coaches Finnish tennis player Harri Heliövaara.