McAvoy was raised in Drumchappel, Glasgow, by his grandparents after his father, also called James and a roofer by trade, abandoned his mother when James Jr. was 7. He went to St. Thomas Aquinas Secondary in Jordanhill, Glasgow, where he did well enough and started "a little school band with a couple of mates".
McAvoy toyed with the idea of the Catholic priesthood as a child but when he was 16, a visit to the school by actor David Hayman sparked an interest in acting. Hayman offered him a part in his film The Near Room (1995) but despite enjoying the experience McAvoy didn't seriously consider acting as a career, though he did continue to act as a member of PACE Youth Theatre. He applied instead to the Royal Navy and had already been accepted when he was also offered ...» read full biography