Nicknamed
Gischi, Westerthaler was a small-built
striker who started his professional career at
FC Wacker Innsbruck and stayed with them for nine years, split by a two-season period at
LASK Linz. With the Tyrolean side he won two league titles and two domestic cups. In 1994, he moved to
SK Vorwärts Steyr only to rejoin LASK two years later. In 1997, he moved abroad and played in Germany for the two major Frankfurt teams and
VfL Osnabrück. In the summer of 2001 he finished his career as a player because of a knee cartilage damage. ==International career==