John McDermott (born 3 February 1969) is an English football coach and former professional footballer As a player, he was a right-back from 1987 to 2007, spending his entire 20-year playing career at Grimsby Town, and holds the club's all-time appearance record, having played 647 league games, 754 games overall for the Mariners. He is one of only 17 players in the history of English football to play more than 600 Football League matches for a single club.