Career
Thofelt was a career officer, graduating from the Royal Military Academy in 1924 and retiring in 1964 in the rank of Brigadier-General. He was an adjutant of the Crown Prince Gustaf Adolf (1938-1947) and King Gustav V (1948-1950). In parallel he served as a sports administrator.
In 1948 he became Secretary-General of the Union Internationale de Pentathlon Moderne, and in 1960–1988 served as its President.
He was also President of the Swedish Fencing Federation (1968) and of the Executive Board of the Swedish Olympic Committee (1969-1976). Between 1970 and 1976 Thofelt was an International Olympic Committee member and later an International Olympic Committee honorary member.