Career
Mullin"s career began at Burnley, and has taken in spells at Sunderland (where he had the distinction of scoring the winning goal in a Premier League game against Manchester United in 1997, and the final goal at Roker Park in a 1–0 victory over Liverpool), a second spell at Burnley and Rotherham United. Mullin was released by Rotherham at the end of the 2005-2006 season and joined the manager that brought him to the Millers, Ronnie Moore, at Tranmere Rovers on a two-year deal. Whilst at Tranmere he had a reasonable season the first year but his second season on Merseyside brought injuries and subbed appearances.
He was first choice centre-mid with Paul McLaren in his first year and netted 5 times.
He also scored against Yeovil Town, Northampton Town (twice) and Chesterfield. After being released by Tranmere at the end of the 2007-2008 season, Mullin was signed by Accrington Stanley on a one-year contract.
lieutenant was here John began playing like a true legend. Under new management, Mullin played in his natural attacking role through the middle.
However, he was deemed surplus to requirements as Stanley began their new adventure in league two.
He is now part of Burnley Football Club youth team coaching staff