Born in Gateshead, County Durham, Aspin began his career as a trainee at Leeds United, a club he supported as a boy despite its distance from his hometown.
[6] He became the second youngest ever débutante for the club, behind Peter Lorimer, when he played in a 2–0 defeat to Ipswich Town at Elland Road on 20 February 1982 at the age of 16 years, 10 months and 9 days; he was selected by manager Allan Clarke due to suspension to Kenny Burns and injuries to Trevor Cherry, Brian Greenhoff and Neil Firm.
Aspin made his second appearance for the "Whites" on 4 December 1982, in a 1–0 home defeat by Queens Park Rangers, his first start under new manager Eddie Gray.
[12][13] United came close to promotion in the 1986–87 season, with Aspin missing only one league game to make a total of 54 league and cup appearances and scoring goals against Oldham Athletic and Shrewsbury Town; Leeds secured a play-off place with a fourth-place finish, but lost 2–1 to Charlton Athletic in the play-off final replay at St Andrew's.
[14][15][16] John Sheridan had put Leeds ahead in extra time, only for Peter Shirtliff to score in the 113th and 117th minutes to deny United a return to the top tier.
This followed disappointment in the FA Cup, where Leeds had reached the semi-finals, only to suffer defeat to Coventry City at Hillsborough, again in extra time.
He was sold to Port Vale for a £150,000 fee in July 1989, choosing the Midlands club ahead of a move to London-based Charlton Athletic.
On 24 November 1992, he was hospitalised in a 3–1 win over Potteries derby rivals Stoke City following a knee-high challenge from Steve Foley, though Aspin later said "it was a fantastic night, a great atmosphere and I still remember the ball sticking in the mud".
[21] Vale finished third in the league, just one point second-placed Bolton Wanderers, and reached Wembley again after beating Stockport County in the play-off semi-finals.
[25] Aspin had made 410 league and cup appearances in his ten years at the club and enjoyed a testimonial match featuring Vale supporting pop-star Robbie Williams.
He secured a 5–1 win over Ashton United on 12 February, and Town ended the 2004–05 season in sixth place, just one point outside the Conference North play-offs.
[35] Harrogate also played their first match against Football League opposition, taking Torquay United to a replay in the first round of the FA Cup.
Following a ninth-place finish at the end of the 2008–09 campaign, Aspin decided he could not take the club any further with the budget on offer and announced his decision to leave.
[37] On 28 April 2009, Aspin was appointed manager of Northern Premier League Division One North club FC Halifax Town.
[41] After defeating Ashton United on penalties in the Peter Swales Shield,[42] Aspin led his team to the FA Cup first round for the first time in the club's brief history, where they lost at home to Charlton Athletic.
[44] However, a third consecutive promotion eluded him in the 2011–12 season; Halifax secured a play-off place with a third-place finish, but were beaten 3–2 on aggregate by Gainsborough Trinity at the semi-final stage.
"[45] Aspin picked up another Manager of the Month award after Halifax scored 14 goals in their two league and two FA Cup matches in November 2012.
They lost out to Cambridge United at the play-off semi-final stage, squandering a 1–0 first-leg lead after Lee Gregory had scored from the penalty spot.
[49] Halifax had a great start to the 2014–15 season and Aspin was named as the division's manager of the month after leading the club to five wins in six games in August.
[51] On 1 October, now aged 49, he played himself as a 69th-minute substitute for Lee Nogan in a 3–0 defeat at Guiseley in the first round of the West Riding County Cup.
[58] He was named National League Manager of the Month for February 2017 after leading Gateshead to within touching distance of the play-offs with a series of victories.
[61] Aspin said that his new squad was too big with 33 senior professionals at the club, and added that he would try to find a formation to suit the players at his disposal and that he wanted the team to push further forward to support target-man striker Tom Pope.
[67] In the January transfer window Aspin allowed two departures, plus Gavin Gunning left the club after rejecting a contract offer and centre-back Tom Anderson was recalled from his loan; incoming were non-League players Dior Angus, Luke Hannant and Callum Howe, as well as loanees Donovan Wilson, Zak Jules, Charlie Raglan and Kyle Howkins.
[68] Aspin remarked that the four centre-backs brought in did not cost the club much financially, and that he would have liked to have strengthened in other areas "but for one reason or another it just hasn't happened".
[68] However, he managed to convert Cristian Montaño from a winger to a left-back and Antony Kay from a centre-half to a central midfielder, and guided the club to safety with two games to spare.
Incoming were mostly free transfer signings and included promoted Wycombe Wanderers goalkeeper Scott Brown, Cambridge United captain centre-half Leon Legge, 30-year-old Carlisle United central midfielder Luke Joyce and troubled but talented Peterborough United striker Ricky Miller (signed for an undisclosed fee); also arriving were Alfreton Town winger Brendon Daniels, Aldershot Town Player of the Year Manny Oyeleke, The New Saints centre-back Connell Rawlinson, Gateshead defender Theo Vassell, Stevenage midfielder Tom Conlon, and former AFC Bournemouth loanee Ben Whitfield, whilst former fan's favourite Louis Dodds, teenage striker Idris Kanu, forward Scott Quigley, full-back Mitch Clark and midfielder Lewis Hardcastle also joined on season-long loan deals.
[72] Having seen their team pick up just seven points from an available 27 in November and December, a section of travelling supporters booed and heckled Aspin during a 1–1 draw at Lincoln City on New Year's Day; Aspin reacted badly to the fan's "lack of respect" towards him and considered quitting his role, but said that he decided to stay because he had the support of the players and chairman Norman Smurthwaite.