From 2001-2006 Tsolis was the head coach for the U-group 2 in Vålerenga Fotball youth department on the men's side and a coach coordinator at the same time. He was also J16 coach for the inter-region team during this period.
In 2005 he started Scandinavian Football School, which was a 2 and 6 month football academy at Mallorca in Spain, for players of the age 16–23 years of age with ambitions to become top players. The football academy swapped name to Mallorca Toppfotball in 2016 and became a 9-month football academy, which offers students to play in Spanish league systems. Leif Tsolis founded at the same time a Spanish football club named F.C. Mallorca Toppfotball, which is affiliated with the academy. Tsolis has built up both the club and the academy, and is the owner of the projects. As a football coach, Tsolis has 8 promotions as head coach with his football teams, and the promotions has taken place both in Norway and Spain. He has none relegate as a football coach.
In 2008 and 2009 he was the head coach for Oslo Allianse FK, combined with being the head coach for Røa IL in the 2008 season.[1] In 2007 he was full-time employed in Finnsnes IL[2] as administrative manager, Project Manager for Sports City center and coach coordinator, combined with minor coach work at the A-team, B-team and J16-team.
In 2010 he was assistant trainer and top player developer in the 1. division club Mjøndalen IF,[3] where he also was the in game coach for the 2nd team and had analysis tasks for the A team. In Mjøndalen he was a contact person against Norsk Toppfotball, Buskerud Top Coach Network and representative on national gatherings and international gatherings.