He represented Cape Breton South in the House of Commons of Canada from 1908 to 1911 as a Liberal-Conservative member.
He was born in Westville, Nova Scotia, the son of William Maddin and Agnes Goode.
Maddin was educated at Pictou Academy and Dalhousie University.
Maddin served overseas during World War I, reaching the rank of major.
After the war, Maddin practiced law in Springhill and Sydney.