[1] After playing just one reserve team game he seriously damaged his knee ligaments in training and after recovering finally made his debut at Vale Park in a 1–1 draw with Middlesbrough on 30 October 1989, coming on as a substitute.
He took up a full-time managerial position at IFA Premiership side Newry City in November 2005,[4] getting the club into the top six in his first season.
He was sacked in May 2007 after just 16 months in the job,[9] he claimed he could "leave with his head held high" after securing a UEFA Cup spot.
[10] A week later he returned to Bangor,[11] but quit that post in May 2008 after claiming an eight-match suspension handed to him by the Irish Football Association hindered his ability to manage the club.
[14] An IFA Commission was set up to investigate the brawl,[15] and Millar was handed a four-game ban, whilst the club were fined £1,200 and Larne player Anthony Lagan was suspended for the rest of the season.
[16] Newry chairman Paul McKenna condemned the lenient punishments, stating that the commission "bottled it",[17] though the IFA ruled that they "acted fully in line with regulations and procedures".
[19] Larne finished tenth in 2011–12, and Millar resigned in April 2012 to take up the position as Gary Hamilton's assistant at Glenavon.
[20][21] After seven years at the club, Millar departed Glenavon on 2 April 2019 and returned to Glentoran as new manager Mick McDermott's assistant.