Which swimmer was the first to break the one-minute barrier for 100-meter freestyle?

Johnny Weissmuller (2 June 1904 – 20 January 1984) was an Austro-Hungarian-born American competition swimmer and actor, best known for playing in films of the 1930s and 1940s and for having one of the best competitive swimming records of the 20th century.

Weissmuller was one of the world's fastest swimmers in the 1920s, winning five Olympic gold medals for swimming and one bronze medal for water polo. He was the first to break the one-minute barrier for the 100-meter freestyle and the first to swim 440-yard freestyle under five minutes. He won fifty-two U.S. national championships, set more than 50 world records (spread over both freestyle and backstroke), and was purportedly undefeated in official competition for the entirety of his competitive career.