Following shakedown from New London, Connecticut, Gurnard sailed for Rosneath, Scotland, 2 November 1942 and reached that port 13 days later.

The patrol was uneventful; no enemy ships were sighted and subsequently Gurnard returned to New London 9 February 1943 for repairs and alterations.

She patrolled off Toagel Mlungui Passage and on 29 June saw action for the first time, damaging two Japanese merchantmen and surviving 24 depth charges thrown by an enemy destroyer.

Following overhaul at San Francisco Gurnard departed Pearl Harbor 16 April on her fifth war patrol, bound for the eastern Celebes Sea.

This vital convoy carried 40,000 troops intended to oppose Gen. MacArthur in New Guinea, and the embarked units suffered losses of nearly 50 percent.

A successful attack was pressed home 3 November at the end of an 18-hour hunt, and two torpedoes demolished cargo ship Taimei Maru.

Gurnard finished her final patrol at Pearl Harbor 9 May and put in at Mare Island, California, nine days later for a major overhaul.

She was sold for scrapping 26 September 1961 to the National Metal and Steel Corporation, Terminal Island, Los Angeles, California Gurnard′s war patrols numbers two through seven were designated "successful."