Mats Karlsson picked up his first pair of drumsticks at the age of 11. After playing in different local bands in the late '80s and early '90s, he ended up in a band called Tears of Sahara, which he formed with Rino Fredh and Christoffer Hermansson (Seventh One).



In 1995 Mats Karlsson decided to go to LA and study music at Musicians Institute. He went back to Sweden for a one year, recorded the cd “Opressor” and a Sepultura-Tribute with the band Ton of Bricks, (feauturing Tony Jelencovich on vocals) made some gigs, and then went of to London to continue his music studies.



Back in Sweden, in 1999, Mats was contacted by his old bandmates Rino and Christoffer, and asked him to join their new band Seventh One.



Mats Karlsson was stand-in drummer for Lost Horizon's Spanish tour. Karlsson joined forces with former Lost Horizon members Daniel Heiman (vocals) and Fredrik Olsson (guitar) in a project called Heed.



During 2004 he also worked together with Lars Chriss of Lion’s Share, helping him out and recorded songs on the pre-production for a new album.



However, Heed parted ways with drummer Mats Karlsson and bassist Jörgen Olsson in December 2005. Karlsson was replaced by Ufuk Demir.