John was born in Liverpool in 1951 and competed as a professional boxer from 1971 to 1980. He held the WBC light-heavyweight title from 1974 to 1978, as well as the European, British and Commonwealth titles between 1973 and 1974. As an amateur, he represented England and won a gold in the middleweight division at the 1970 British Commonwealth Games. He was the subject of This Is Your Life in 1974.
He has appeared on the BBC television programme Sporting Legends and in films such as Man at the Top, The Stud and Tank Malling, and made a starring appearance in the television show Boon in 1989. He appeared on a boxing special of The Weakest Link in 2009, where he finished in third place.
John was appointed Member of the Order of the British Empire in the 2017 Birthday Honours for services to boxing.
This is the second time John has been appointed Captain of Variety Golf having previously filled the role in 2002.