 He was awarded the sword of honour at Royal Military College of Canada in 1891 and the Governor-General gold medal.His father was Senator Donald MacInnes from Hamilton, Ontario, and his mother was the fourth daughter of Sir John Robinson, 1st Baronet, of Toronto.Duncan Sayre MacInnes married May Millicent Wolferstan Thomas, the daughter of a prominent Montreal banker, Francis Wolferstan Thomas, and his first wife, Harriet, daughter of The Hon.