Mac was born and grew up in the highlands of Scotland. The mountains have always featured in his life. Since the early seventies Mac has worked as an instructor and mountain guide in the mountains of UK, the Alps and the Greater ranges. He spent a great deal of time living and working in the Alps and Canadian Rockies.

Mac is a member of the British Association of Mountain Guides (BMG) which was formed in 1975 and, along with many other mountainous counties, is a member of the International Federation of Mountain Guides Association (IFMGA) which sets the standard for the training of guides world wide. The IFMGA badge worn by guides has become the assurance of the highest professional and technical standards.