[2] He won a bronze medal in the men's 300 m rifle prone (300FR60PR) at the 2008 European Shooting Championships in Granada, Spain, accumulating a score of 599 points.

Muller is also a member of Sportschützen Taters, and is coached and trained by former Olympian Wolfram Waibel Jr. of Austria.

[1] Muller represented Switzerland at the 2008 Summer Olympics, where he competed in the men's 50 m rifle 3 positions, along with his teammate Marcel Bürge.

He was able to shoot 395 targets in a prone position, 380 in standing, and 389 in kneeling, for a total score of 1,164 points, finishing only in twenty-first place.

[3] At the 2010 ISSF World Shooting Championships, he won a gold medal the 300m standard rifle team event, along with teammates Marcel Bürge and Olivier Schaffter.