After starting his career with local side Coleraine F.C., Peacock moved on to Belfast club Glentoran in 1947. After two years he was signed by Glasgow club, Celtic, where he would go on to become captain and a club legend. During his time at the club he won one league title, two Scottish Cups and two Scottish League Cups.
Peacock won 31 caps for Northern Ireland. He featured alongside Harry Gregg, Danny Blanchflower and Billy Bingham in the team that reached the quarter-finals of the 1958 World Cup, the country's joint best result to date - they reached the equivalent of the quarter finals in 1982. He became Northern Ireland manager a year after his retirement as a footballer in 1961, giving George Best his first start. In the 1960s Peacock returned to Coleraine, winning the Irish League title in 1974.
He was also assistant manager to Billy Bingham during Northern Ireland's 1982 World Cup campaign, where they famously knocked out hosts Spain in Valencia.
Alongside Jim Weir and Victor Leonard, Peacock was one of the founders of the Milk Cup. Held in his native Coleraine, the youth football competition started with sixteen teams in 1982 and rose to become one of the most respected tournaments in the world.
In 1986 He was awarded the MBE for his services to football. He died in 2004, aged 76.
In June 2006 a statue of Peacock was commissioned. The memorial stands in Coleraine and was unveiled in July 2007, at the opening of the 25th Milk Cup.
Also in 2006, a youth football club was formed in honour of Bertie, Bertie Peacocks Youths. This club has a range of teams from under 9 to under 14. In only 2 years, the teams have been very successful - the under 11's in particular, winning the Down and Connor League, the Down and Connor Knock-Out Cup and becoming Northern Ireland Boys Champions all in the 2008 season. This club has had much encouragement from the wide supporters of Bertie Peacock.