Blackpool Born in
Liverpool, Mangan began his career with
Blackpool at the age of 15. He was with the club for three years, scoring 49 goals in reserve and youth team football. Mangan made his professional debut at the age of 17 in a 1–0 defeat to
Chesterfield on 24 April 2004. He made just one further professional appearance at Blackpool under
Steve McMahon's management and his replacement,
Colin Hendry, loaned Mangan to
Northern Premier League Premier Division side
Hyde United. He scored two goals in seven appearances, helping the club to secure the league title. Mangan was released by Blackpool at the end of the
2004–05 season.
Accrington Stanley Mangan was heavily linked with a return to Hyde the following season, but he rejected them in favour of a full-time contract with
Conference Premier side
Accrington Stanley, after impressing during the club's pre-season schedule. After making his debut in a 1–0 win over
Canvey Island on 13 August 2005, Mangan scored his first goal for the club in his third appearance during a 3–1 defeat to
Cambridge United. In his first full season, Mangan played in 45 league and cup games, scoring ten goals, and was primarily used as a substitute. His goals helped Accrington gain promotion to
The Football League at the end of the
2005–06 season; the first time the club had achieved this in 50 years. In his second year at the club, Mangan became frustrated with his lack of starts. From his 38 total appearances, of which only five were made in the starting XI, he scored six goals. At the end of the 2006–07 season, Mangan was offered a two-year deal by Accrington, but rejected it in favour of
League Two side
Bury, having appeared in a pre-season friendly for the club against
Everton.
Bury in 2007 At Bury, Mangan scored his first goal on 7 September 2007 with a header against Chesterfield, with five more goals coming before Christmas. He was injured at the beginning of December 2007 with a suspected hernia problem and later underwent surgery, restricting him to just six appearances in the rest of the season as he struggled to regain fitness. He made a total of 26 appearances in all competitions while with Bury. Following the sacking of Bury manager
Chris Casper, Mangan was allowed to return to Accrington Stanley by his replacement
Alan Knill on a one-month loan deal, scoring one goal in seven appearances. Mangan was released by Bury towards the end of the 2007–08 season.
Forest Green Rovers In the summer of 2008, Mangan signed for
Forest Green Rovers in the
Conference Premier. It was at Forest Green that Mangan's goalscoring reputation began to form; his first season saw him finish as the league's top scorer with 26 goals in 41 games. Including cup competitions, Mangan made 49 appearances for the club, scoring 30 goals. These included hat-tricks against
Torquay United,
Lewes and
Rushden & Diamonds. Mangan was voted player of the year by the Directors of Forest Green Rovers.
Wrexham On 20 January 2009, Mangan completed a move to
Wrexham for an undisclosed fee, making his debut on 23 January in a 1–0 victory over
Wimbledon, before scoring his first goal seven days later in his third appearance during a 3–1 over
Altrincham. Mangan then scored his first home goal for Wrexham in a 2–1 victory over Mansfield Town. He ended the 2009–10 season with nine goals, the club's joint top scorer in a campaign which saw the side finish 11th. Mangan started the next season in an unfamiliar
left-wing position; despite this he still finished as the club's top scorer with 16 league goals, helping them to the play-offs, where they lost to
Luton Town.
Fleetwood Town in 2012 On 1 June 2011, he signed for
Conference Premier side
Fleetwood Town. It was announced on 7 May 2013, that Fleetwood would not be offering the striker a new contract, and would therefore be released.
Forest Green Rovers (second spell) On 16 May 2013, Mangan returned to former club
Forest Green Rovers on a three-year contract. He made his second debut for the club on 7 September 2013 in a draw with
Braintree Town. On 5 February 2014, several months after he had been suspended by the club in October 2013, he had his contract terminated. Mangan appealed against his dismissal from the club, so remained a registered Forest Green player pending the outcome of the appeal. He subsequently joined
Conference Premier leaders
Luton Town on loan on 1 April 2014 for the remainder of the
2013–14 season. In June 2014, it was announced that Mangan had won his appeal against Forest Green and had returned to the club under his previous contract as a player.
Shrewsbury Town On 24 July 2014, it was announced that Mangan had signed a one-year deal at
League Two club
Shrewsbury Town. He made his Shrewsbury debut as a substitute away at
A.F.C. Wimbledon on 9 August, and scored his first goal for the club a week later against
Tranmere Rovers, also providing an assist for
Mickey Demetriou's] injury time winning goal at
New Meadow. Mangan earned his first start for the club three days later, scoring twice and winning a penalty in a 4–0 win over former club
Accrington Stanley. On 26 August, he scored the only goal from a free kick as Shrewsbury won away at
Leicester City, knocking the
Premier League opponents out of the League Cup. The club ultimately reached the fourth round of the competition, drawing
Chelsea at home. Mangan scored a late goal to level the scores at 1–1, just moments after entering the field as a substitute, although Chelsea restored their lead minutes later to win the tie 2–1. By the end of October 2014, Mangan was joint top scorer at Shrewsbury, alongside
James Collins, having scored six goals in all competitions. His seventh goal came days after the Chelsea match, equalising with a half volley away at
Dagenham and Redbridge, before winning an injury time penalty which was converted by teammate
Liam Lawrence to secure Shrewsbury's fifth straight win in the league. The requirement to carefully manage an ongoing knee injury restricted Mangan's match time over the next few months, although he still managed to score a late winner against
Morecambe in December after coming on as a substitute. He marked his first start since November by scoring a brace and providing an assist in a 3–0 home win against
Hartlepool United on 17 January 2015, to help move Shrewsbury back into the
League Two automatic promotion places. Shrewsbury were subsequently promoted back to
League One at the first attempt, following a 1–0 away win at
Cheltenham Town in April 2015, however due to
Financial Fair Play restrictions, they were unable to offer Mangan an extension to his contract.
Tranmere Rovers Mangan joined
Tranmere Rovers of the
National League on 2 July 2015, signing a one-year contract. He scored seven goals in the first half of the season, including five in four matches during September and October, but lost his place in the team due to injury and manager
Gary Brabin's subsequent tactical switch to a 4–5–1 formation with
James Norwood preferred in the lone strikers role.
Shrewsbury Town (second spell) After losing a regular place at Tranmere, Shrewsbury Town made an enquiry about Mangan's availability in the next transfer window. He rejoined the club on an 18-month contract on 7 January 2016. He made his return debut in an
FA Cup tie away at
Cardiff City three days later, scoring the only goal in a 1–0 victory, sending Shrewsbury through to the fourth-round for the first time since
2002–03. He missed a penalty on his home return against
Barnsley, but scored a second-half equaliser at
Burton Albion the following week, with Shrewsbury going on to win 2–1 at the league leaders. Mangan scored five goals in nineteen league appearances in the second half of the
2015–16 season to help the club avoid relegation to League Two. During the 2015−16 season Mangan received the PFA community champion as recognition for his work with children in the Shrewsbury area.
Return to Tranmere Rovers Mangan re-joined
Tranmere Rovers for an undisclosed fee on 4 November 2016. He was released by Tranmere at the end of the 2017–18 season.
Bala Town On 17 June 2018, he joined
Welsh Premier League side
Bala Town. He made his debut for the club on 28 June 2018 in a 3–0 away
Europa League preliminary round first leg defeat to
S.P. Tre Fiori.
Accrington Stanley Mangan departed Bala without playing a league game for them after receiving an offer from
Accrington Stanley. ==Coaching career==