Most well known for his famous rendition of the traditional ballad "Danny Boy," he is also notable for his platinum albums Love Is a Voyage; Old Friends; and Christmas Memories, as well as for his membership in the popular band The Irish Tenors.
In the early 1980s, he established a music group called The Mistletones. A decade later, after recording the wildly popular single "Danny Boy," he toured with both The Chieftains and The Seekers.
He hosted several CBC music specials and was the subject of the 2002 PBS program John McDermott: A Time to Remember.
He spent the first ten years of his life in Glasgow, Scotland, and the remainder of his youth in Toronto, Ontario, Canada.
He and rock singer David Clayton-Thomas both contributed to a 2010 charity recording titled World Jazz for Haiti.