In 2012 he was appointed Austria's Davis Cup captain and in his first year took the team to the World Group quarter-finals, for the first time since 1995. The Austrians were relegated in 2013 and after their 2014 campaign, in which they were unable to return to the World Group, Trimmel was replaced by Stefan Koubek. He also captained the Austria Fed Cup team in the 2014 season.