He competed at the 1924, 1928, 1932 and 1936 Summer Olympics, winning a total of four gold, three silver and one bronze medals.

Switzerland did not send an Olympic team in 1932 due to the economic depression, but Miez volunteered to compete on his own and also returned the body of his brother who died in the United States.

After winning a silver on the floor, Miez withdrew from the Games and toured the United States giving presentations at universities.

[2] Miez retired after the 1936 Games and worked as a national gymnastics coach and then as a Red Cross official.

After World War II he founded several private schools, wrote books on sports medicine, and coached tennis.