He was the younger son of Hugo MacColl, a master marine engineer.
MacColl was educated at Sedbergh School and Balliol College, Oxford.
[1] Following his graduation he received a Commonwealth Fund fellowship and spent two years at University of Chicago in the United States.
[1] He subsequently moved to Paddington, London, and became a member of the borough council.
[2] MacColl believed in the importance of local government and co-authored two books on the subject.