4. Joe Louis

Before he enlisted in the Army, Joe Louis had already won 52 bouts (against 1 loss) and had defended the World Heavyweight title 20 times. He was arguably one of the most famous athletes to join the military, especially in the prime of his career.

Louis was initially assigned to a segregated cavalry unit at Fort Riley, however, given his star potential, the Army later reassigned him to the Special Services Division where he championed support for the war and assisted in recruiting African-American men to join the Army. Though he never served in combat, Louis’s military career (1942-1945) helped ease racial tensions, boosted morale across the United States, and saw him become the first African-American widely revered and respected by the whole country.

When he retired from boxing in 1951, Joe Louis won 66 fights (52 by knockout) and lost just three times. He held the World Heavyweight title for twelve consecutive years from 1937 to 1949 and defended it a record 25 times.