Educated in Leipzig, Germany, Dietrich Wortmann came to the United States and competed in the 1904 Olympic wrestling competition. Although a German citizen in 1904, he represented the German-American Athletic Club of New York at the Olympics.
As a wrestler, Wortmann was US champion in 1906 in the welterweight class. He stayed in America and became prominent in weightlifting circles, eventually becoming chairman of the AAU weightlifting committee in 1936. In 1951 he was named President of the Fédération Internationale de Halterophile (FIH), then the International Weightlifting Federation. For more than 45 years he served as President or Honorary President of the German-American Athletic Club. He was also President of the Metropolitan Association of the AAU from 1949-51. Wortmann made his career as an architect in New York City.