More international successes followed at the World Sprint Championships, where he won bronze in 1976 and silver in 1977.

His last appearance as a speed skater was at the 1980 Winter Olympics in Lake Placid, where he placed 5th in the 1,000 m, 1.93 seconds behind the winning time of Eric Heiden.

Mueller was fired as coach of the Norwegian team in November 2009, due to allegations of harassment of skater Maren Haugli.

[2] Mueller was married to American speed skater Leah Poulos, two times World Sprint Champion and three times Olympic silver medalist, and had two children.

An autobiography, called Op dun ijs ("On thin ice"), was published in the Netherlands in 2006.