Born: 28 July 1993, Streatham, London

Position: Striker

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McCallum joined Isthmian League club Dulwich Hamlet as a schoolboy, making his debut for the club's first team at the age of 15. Scored eleven goals as Dulwich Hamlet reached the FA Youth Cup third round in 2010/11, defeating Yeovil Town before losing out to Newcastle United. 
McCallum was snapped up by West Ham United from under the noses of a host of Premier League clubs in January 2011. The south London-born centre forward is blessed with strength, aerial ability and a knack for scoring goals with both his head and his feet - traits he immediately showed in the Hammers' reserve team on his arrival at the Boleyn Ground.
Joined League Two club Rochdale on loan in January 2012, but his spell was cut short by shin splints, but McCallum's growing pains soon cleared up and he enjoyed an outstanding 2012/13 campaign, scoring regularly for the Development Squad before impressing during a loan stint with League Two clubs AFC Wimbledon. However, it didn't start well, sent-off on his Football League debut for the Dons at Morecambe on 24 November 2012. Scored his maiden senior goal in AFC Wimbledon's 3-2 League Two win at Torquay United on New Year's Day 2013. Completed his loan spell with four goals in nine appearances before he was loaned to League Two side Aldershot Town on 8 March 2013. Scored three goals in nine appearances for Aldershot Town before returning to West Ham United on 28 April 2013. Totalled 13 goals in 33 Development Squad and Football League appearances for three clubs.
Signed a new contract with West Ham United in January 2013. Appeared in first-team pre-season matches at Cork City - where he scored - Borehamwood and AFC Bournemouth in July 2013. Scored three goals in six games during a loan spell with League Two club Torquay United in October-November 2013. Loaned to Scottish Premier League club Heart of Midlothian in January 2014, totalling seven appearances for the Jam Tarts. Scored once in three Development Squad appearances in 2013/14. Joined League Two club Portsmouth on loan in January 2015, making seven appearances.
McCallum joined League Two club Leyton Orient on a two-year contract on 19 June 2015. He made his league debut for Orient against Barnet on 8 August 2015. The striker wasn't offered a new contract at the end of the 2016–17 season and left Orient. Later played for Eastleigh, Solihull Moors, Barnet, Dagenham & Redbridge, Chesterfield, before returning to Eastleigh in may 2023.