Jack Sieg
| Personal information | |
|---|---|
| Born | December 10, 1914 Kansas City, Missouri, United States |
| Died | December 21, 1968 (aged 54) Oklahoma, United States |
| Sport | |
| Sport | Swimming |
| Club | University of Iowa |
Jack George Sieg (December 10, 1914 – December 21, 1968) was an American swimmer who used the butterfly stroke in 1935, developed by his coach Dave Armbruster. He competed for the University of Iowa and first used the stroke in a breaststroke leg of a medley relay February 25, 1935.