As a child, Kelly suffered from Legg–Calvé–Perthes disease but recovered to win a move from non-League Alvechurch and turn professional at Walsall in 1983.
Following brief spells with Sheffield United, Motherwell, and Mansfield Town, he finished his career at Derry City, winning the 2002 FAI Cup in his final match as a player.
At that stage, he worked as a trolley porter at Cadbury whilst representing the youth team at non-League side Alvechurch.
[8] He went on to have a week-long trial at Bayern Munich but did not join the club despite Uli Hoeneß reportedly comparing him to Denis Law.
[11] He scored a total of 82 goals in 190 league and cup appearances throughout five seasons at Fellows Park, and the transfer fee received for him remains a club record.
[13] His stay at the Boleyn Ground proved to be largely unsuccessful as an initially promising strike partnership with Leroy Rosenior floundered as he scored only six goals in 25 First Division games as John Lyall's "Hammers" suffered relegation in 1988–89.
[14] Kelly also failed to find form for the club under new boss Lou Macari in the Second Division, scoring just two goals in 24 matches of the 1989–90 campaign.
[15] He was then the club's top-scorer with 28 goals from 57 games as Kevin Keegan steered Newcastle to promotion into the Premier League as champions of the First Division.
[15] In his final game for United, on the last day of the season against his old club Leicester City, Kelly and new strike-partner Andy Cole both scored hat-tricks in a 7–1 win at St James' Park.
[16] He was named as Newcastle United's Player of the Year, but was allowed to leave the club due to the return of Peter Beardsley.
Kelly remained a highly popular figure at Newcastle, even commanding a standing ovation upon returning to St James' Park in Sunderland colours.
[17] Kelly did not make the move back to the top-flight with Newcastle as he was transferred to First Division side Wolverhampton Wanderers in June 1993 after manager Graham Turner paid £750,000 to secure his services.
[4] He remained a regular player at Roker Park in the 1996–97 campaign but failed to score a single goal all season, often being used as a right-sided midfielder rather than a striker.
In June 2001, he turned down a coaching role at United and instead signed a two-year contract with Billy Davies's Motherwell in the Scottish Premier League.
[23] He scored four goals in 17 games as Stuart Watkiss's "Stags" leapfrogged Cheltenham Town in the race for the final automatic promotion place.
[31] He was unable to play in the 1998 FIFA World Cup qualification play-off fixture with Belgium after picking up an ankle injury.
[37] He was named as assistant manager to Davies at Derby County in July 2007, a few weeks after the club achieved promotion to the Premier League.
[41] He and Davies were sacked by Forest in March 2014, and he settled out of court with the club over alleged unpaid bonuses and for breach of contract.