Jon Sieben is a swimmer who has competed for Australia. He competed at the 1984, 1988, and 1992 Summer Olympic Games.
At his first Olympics in 1984, Sieben produced a late charge through the midway of the final length to upset a field of experienced swimmers that included Michael Groß and Pablo Morales for a surprising gold medal in the 200 metres butterfly. Sieben's time of 1:57.04 erased a hundredth of a second from Groß' world record. He also swam through the butterfly leg in the preliminary heats of the 4x100 metres medley relay before his teammate Glenn Buchanan replaced him on the Australian men's team that finished third in the final.
When he returned to his second Games four years later in Seoul, Sieben's butterfly stroke waned, citing a spate of shoulder injuries. Unable to defend his 200 metres butterfly title, he switched to a sprinter version. There, he managed to beat Groß again near the wall but narrowly missed the podium by 0.03 of a second.
Sieben ended his swimming career after finishing seventh with the Australian men's team in the 4x100 metres medley relay and landing on the tenth overall spot in the B-finals of the 100 metres butterfly at Barcelona 1992.
Olympic Results[]
| Year | Event | Rank |
|---|---|---|
| 1984 | Men's 200m butterfly | 
|
| Men's 4x100m medley relay | 
| |
| 1988 | Men's 100m butterfly | 4th |
| Men's 4x100m medley relay | 6th | |
| 1992 | Men's 100m butterfly | 10th |
| Men's 4x100m medley relay | 7th |
1984[]
| Discipline | Round | Time | |
|---|---|---|---|
| 200 metres butterfly | Heats | 1:59.63 | |
| A Final | 1:57.04 | AR | |
| 4x100 metres medley relay | Heats | 3:43.93 (54.24 split) |
|
| Final | 3:43.25 (Reserve) |
AR |
1988[]
| Discipline | Round | Time |
|---|---|---|
| 100 metres butterfly | Heats | 53.85 |
| A Final | 53.33 | |
| 4x100 metres medley relay | Heats | 3:47.40 (54.65 split) |
| Final | 3:45.85 (53.42 split) |
1992[]
| Discipline | Round | Time |
|---|---|---|
| 100 metres butterfly | Heats | 54.67 |
| B Final | 54.73 | |
| 4x100 metres medley relay | Heats | 3:43.78 (54.73 split) |
| Final | 3:42.65 (54.78 split) |