Buchan was born in Bulawayo, the son of white Rhodesian immigrants from Scotland. He farmed maize and cattle in Zambia until moving to Greytown in kwaZulu-Natal in 1976 to farm. His wife Jill explained the decision to leave Zambia in a 2009 video, saying “We always agreed that when we had children we’d bring them up ourselves and not send them away. That’s actually why we left Zambia, we didn’t want to put them on a plane and send them far from home.”
In 1980 Buchan started Shalom Ministries to preach in his local community. Over time he became a full-time evangelist, handing over the day-to-day running of his farm business to his sons.
In 1998 Buchan wrote a book about his life, Faith Like Potatoes, the book was turned into a film of the same title in 2006. Angus Buchan’s Ordinary People is a 2012 semi-biographical film that tells the story of the growth of Buchan’s ministry from the 1970s to the present, and that of three fictional characters whose lives are changed after attending one of his conferences.