The Welsh international goalkeeper made his name at Prenton Park with Tranmere Rovers before Grimsby Town snapped him up ad he continued his good form between the sticks there. He'd won Welsh U21 caps and a Welsh senior cap when Leicester brought him to the Walkers Stadium before the start of the 2003-04 season.
Coyne knew he was probably going to play second fiddle to Ian Walker during his time at the club, but the lure of Premier League football was too strong to turn down. Coyne was, therefore, used as back-up to Walker. He made his debut as a substitute in a Foxes side already well-beaten against Manchester United - a bit of a no-win situation - and made his full debut in a League Cup tie away at Aston Villa, doing little wrong.
His only top-flight start came when Walker was suspended, at Bolton Wanderers, and his frustrations at being second choice eventually boiled over and he left City following their relegation to join Burnley. He returned to Tranmere after his spell at Turf Moor to bring his career to a close.