He signed a new two-year contract extension with Hamilton in April 2012.[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.[6]
In July 2014, Millar signed for Stenhousemuir again, this time on a one-year contract.[7] Millar left Stenny after three years with the club, signing for East Fife on 29 May 2017.[8]
In May 2018, Millar signed for Airdrieonians.[9] At the end of the 2018–19 season, he signed a new one-year contract.[10]