He signed for United in 1993, making the step up from non-league, having first pulled on the United ‘keeper’s jersey as a youngster back in December 1991 in a Northern Intermediate League game against Middlesbrough.
Eventually breaking into the first team, he played in the 1999 FA Cup Final against Manchester United in his tenth senior match.
In 2002/03, Harper kept goal - and a clean sheet - in the memorable UEFA Champions League victory over Juventus at St. James' Park and he is also remembered for saving the penalty at Watford in November 2006 which earned United their first competitive penalty shoot-out success.
Harper passed the 100-game mark for United during 2007/08 and took over the undisputed United number 1 jersey when Shay Given left for Manchester City in February 2009.
From the start of the 2009/10 season, Harper - after conceding at West Brom on the opening day of the season - went 501 minutes without shipping a goal.
Solid, reliable and a popular and supportive figure in the dressing room, Harper holds the record of keeping the most clean-sheets in a season for the club (21), passing Willie McFaul’s previous individual best and setting the best overall in any United season.
He was awarded the Wilkinson Sword by Sport Newcastle on 12 March 2012 for services to sport and the community.
Harper became United’s oldest European performer when he lined up for the Magpies in Atromitos in August 2012 (37 years and 162 days).
He is now passing his experience and expertise on to a new generation as a goalkeeping coach at the club's Academy and is a respected BBC TV and radio pundit.