[2] His first international appearance was at the 1990 World Rowing Junior Championships – winning bronze in his single scull (1x).

He first competed at the senior level in 1991, and at the age of 19, finished 11th at the World Rowing Championships in Vienna in the single scull.

Müller showed a first dominating season in his single with winning the Overall FISA Rowing World Cup and World Cup Races in Paris with a time of 6.38, Lucerne with a new 'Rotsee' record also below 6.40 and the Diamond Sculls at Henley Royal Regatta.

After spending two years in Providence, Rhode Island, attending Brown and rowing his single scull, Müller moved to Newport Beach, California, which offered a better climate for year-round training.

He won decisively besting Derek Porter who had led the whole race, and his childhood hero, and two-time Olympic Champion Thomas Lange who finished third.

But at the World Rowing Championships, Waddell had the best race of his life pushing Müller back to second.

Leading up to the 2000 Sydney Olympics, Müller entered World Cup race in Vienna, where he finally beat Waddell after four consecutive second-place finishes.

In the finals, in addition to his rival two-time reigning World Champion Rob Waddell, Müller faced former World Champion and Olympic silver medalist Derek Porter and rising star Marcel Hacker.