At the 1989 FIS Nordic World Ski Championships in Lahti, his team ranked 11th in the 4 × 10 km relay.

In the winter of 1989/1990 he had his best World Cup finish with a third in Canmore, Canada.

At the 1999 FIS Nordic World Ski Championships in Ramsau, he won gold in 4 × 10 km relay with his relay teammates Alois Stadlober, Mikhail Botwinov, and Christian Hoffmann.

Since 2003, and also at the 2006 Winter Olympics in Turin, Italy he has been director of the Austrian biathlon and cross-country teams.

[1] The bans on Gandler and 11 others were subsequently rescinded in 2009, after the International Ski Federation dropped doping charges against Gandler, biathlon coach Alfred Eder and cross-country ski coach Gerald Heigl.