Dennis was born on 30 October 1913 in Yarmouth, Nova Scotia, the son of Dennis and Margaret Comeau. He had seven brothers, James, Delbert, Gordon, George, Alfred, Joseph Frederick and Joseph Renee along with three sisters, Annie, Mary and Margaret.
He left school at 13 and worked in a bakery to support his family. This was followed by a string of jobs, a pin-boy in a bowling alley, a mechanic’s helper in a garage, taxi driver and finally tractor driver and maintenance man for the Arcadia Construction Company. During this time, he married Mary Bernice LeBlanc.
Dennis enlisted into the Canadian Infantry on 14 November 1943 in Halifax, Nova Scotia, aged 30, serving in Canada until July 1944 when he embarked for the United Kingdom. He arrived in France on 6 October 1944, but not long after, on the 25 October, was killed in action in Belgium aged 33.
His final resting place is in the CWGC cemetery at Schoonselhof, Belgium in plot III.H.6.