He has played for Hamilton Academical, Stenhousemuir, East Fife, Airdrieonians and Stranraer.
Millar made his senior debut for Hamilton Academical on 14 May 2011, in a 2–1 loss against Inverness Caledonian Thistle.
[4] After missing the whole of the 2012–13 season to date due to injury, Miller returned to action in February 2013 after appearing in an under-20 match.
[5] Millar left the club by mutual consent in August 2013, with a view to returning in the coming months, once he was clear of injuries.
[7] Millar left Stenny after three years with the club, signing for East Fife on 29 May 2017.