McDonald met his wife Ardell while playing junior hockey for the Medicine Hat Tigers. They were married in 1975, and have four children: daughters Andra and Leah, and sons Barrett and Graham. The family settled in Calgary after McDonald's trade to the Flames. They also maintain a summer home in Montana, where the family has invested in restaurants and a craft brewery in the community of Lakeside. Co-owned by Andra, the brewery considers McDonald its inspiration, and produces "Old 'Stache Porter" in his honour.