Douglas Gordon Cunningham CBE DSO ED QC was born in Kingston, Ontario (ON), son of Arthur Breden Cunningham and Katherine (Gordon) Cunningham both of Kingston. He was educated at Kingston Collegiate, Upper Canada College, Toronto ON, Royal Military College, Kingston and Osgoode Law School, Toronto.

In 1933, he was called to the Bar of Ontario and in 1946 he was created King's Counsel which later became Queen's Counsel (QC) when Elizabeth II ascended to the throne. At the beginning of WW2, Captain Cunningham commanded the Camerons of Canada and later commanded the 9th Canadian Infantry Brigade.

He was awarded the Distinguished Service Order for gallantry and distinguished services in the field of battle. In addition to his law practice, Cunningham was a director of several companies. In November 1939, he married Isabelle Simpson, daughter of Mr. and Mrs. Huntington Simpson of Kingston. They had two sons; John Douglas and Ian Simpson.