She was built by John I. Thornycroft & Company at Woolston, Hampshire and commissioned into the RCN on 21 May 1931 at Portsmouth, England. Saguenay and her sister were the first ships specifically built for the RCN. Her first two commanding officers went on to become two of the most important Admirals of the Battle of the Atlantic. She arrived in Halifax, on 3 July 1931.
For the first month of Second World War, Saguenay was assigned to convoy duties in the Halifax area. In late September 1939, she was assigned to the American and West Indies Squadron based at Kingston, Jamaica. On 23 October 1939, the German-flagged tanker Emmy Friederich scuttled herself on encountering Saguenay in the Yucatán Channel, and thus became the Canadian destroyer's first war conquest. In December 1939, Saguenay returned to Halifax to join the local convoy escort force, with which she remained until 16 October 1940, when she was transferred to Greenock, Scotland to serve as a convoy escort on the North Atlantic run. On 1 December 1940, Saguenay was torpedoed west of Ireland by the while escorting Convoy HG-47, and managed to return to Barrow-in-Furness, escorted by, largely under her own power, but with 21 dead and without most of her bow; she was under repair in Greenock until 22 May 1941. After repairs at Greenock, she returned to sea on 22 May 1941. Saguenay was assigned to Escort Group C-3 escorting convoys ON-93, HX-191, ONS-104, SC-90, ON-115, HX-202, ON-121, SC-98, ON-131, HX-210 and ON-141 prior to a collision while escorting SC-109. On 15 November 1942, Saguenay was rammed by the Panamanian freighter Azra off Cape Race, Newfoundland. The impact of the collision set off Saguenays depth charges, which blew off her stern. She made port at Saint John, New Brunswick, where her stern was plated over. On 23 May 1943, Saguenay was transferred to Halifax, to serve with the Western Ocean Escort Force working from Halifax and St. John's, Newfoundland. In October 1943 Saguenay was towed to Digby, Nova Scotia, as a tender assigned to, the Royal Canadian Navy's training depot for new entries. She was used for teaching seamanship and gunnery until 30 July 1945, paid off in late 1945, and broken up in 1946.
