This was John Wayne's first picture under a new Warner Bros contract which paid him $150,000 per film plus ten per cent of the gross, all of which made him a fortune until he was virtually bankrupted by poor legal advice and by the costs of his own production of The Alamo. Like most of Wayne's war pictures, Operation Pacific is gung ho, action-packed and grossly sentimental the plot takes in homeless children, dewy-eyed nuns, a batch of dud torpedoes and marital difficulties. Wayne, of course, takes everything in his stride, scuppering the Japanese fleet, playing daddy to the youngsters and winning back the hand of Patricia Neal, with whom he would be reunited in the 1965 Pacific epic, In Harm's Way. The navy liked this one so much it held regular screenings at all its bases.

During WWII, Duke E. Gifford is second in command of the USS Thunderfish, a submarine which is firing off torpedoes that either explode too early or never explode at all. It's a dilemma that he'll eventually take up personally. Even more personal is his quest to win back his ex-wife, a nurse; but he'll have to win her back from a navy flier who also happens to be his commander's little brother.