He was born in Colchester County, Nova Scotia and became a printer and publisher.

The son of Henry Parnell Dennis, he was educated in Colchester County and entered work as an apprentice printer in Halifax.

[1] He became publisher of the Halifax Herald in 1920 after the death of William Dennis.

[2] Dennis was also a director for the Nova Scotia Trust Company.

[1] He was appointed to the Senate for the Halifax, Nova Scotia division on 3 February 1932 nomination by Prime Minister R. B. Bennett.