John Oster was born on December 8, 1978, in Boston, Lincolnshire. He made his name as a teenager playing for Grimsby before his 1.5 million pound move to Everton in 1997. He moved to Sunderland in 1999 for a fee of 1,000,000 pounds but achieved very little in his time there, making just 70 appearances in the 6 years he was at the club. Since then he has not stayed at any club for long periods of time and while he was on loan to Leeds United he was disciplined twice in one month.