| Roles | Competed in Olympic Games | |
|---|---|---|
| Sex | Male | |
| Full name | Jacobus Hermanus Hendrik Jan "Koos"•de Jong | |
| Used name | Koos•de Jong | |
| Born | 7 April 1912 in Rotterdam, Zuid-Holland |  NED |
| Died | 20 August 1993 (aged 81 years 4 months 13 days) in Capelle aan den IJssel, Zuid-Holland | NED |
| NOC | Netherlands | NED |
| Medals | OG |
| Gold | 0 |
| Silver | 0 |
| Bronze | 1 |
| Total | 1 |
| Games | Discipline (Sport) / Event | NOC / Team | Pos | Medal | As | |
|---|---|---|---|---|---|---|
| 1948 Summer Olympics | Sailing | NED |
Koos de Jong | |||
| One-Person Heavyweight Dinghy, Men (Olympic) | 3 | Bronze | ||||
| 1952 Summer Olympics | Sailing | NED |
Koos de Jong | |||
| One-Person Heavyweight Dinghy, Men (Olympic) | 4 |
