[4][5] An attacking midfielder, he was regarded as one of the most promising youngsters in the country when he came into the first team at St Mirren, then playing in Scotland's second tier.
[3][7][5] His move to the Dons was not a success, with the club in decline after a period as one of the strongest teams in Scottish football, while the manager who signed him (Roy Aitken) was dismissed within weeks of Gillies joining, and he suffered from several injuries and was abused in the street by frustrated supporters as his career stalled.
[6] In 2000 he returned to St Mirren, initially on loan, soon followed by a permanent move after he helped the club win the First Division to achieve promotion to the Scottish Premier League, although they were relegated in 2001.
[10] He spent a year as player-coach in New Zealand with Jonathan Gould at Hawke's Bay United before returning to Scotland for a short spell at Stranraer,[11] retiring from playing in 2008.
Gillies later worked as a football agent,[12] as a trainer for ProAcademy coaching[13] and as Director of Operations for the ProLegal Group in conjunction with PFA Scotland.