Pirnbacher, who started for SC Fieberbrunn , made his international debut in the context of the Ski Jumping Continental Cup in the 1994/95 season. In his first season he reached 71st place in the overall ranking with 128 points. On January 6, 1995, he started his first and only competition in the Ski Jumping World Cup on the Paul-Ausserleitner-Schanze in Bischofshofen . With rank 37, however, he narrowly missed the points. In the summer of 1995 he started at the Ski Jumping Grand Prix . Here, too, he achieved a total of 89 points in the four competitions and thus in the end 68th place in the overall Grand Prix standings.
After his career, among other things, he was an employee and trainer at the Federal Sports and Leisure Center on the Kitzsteinhorn .