Born in Kihelkonna Parish, Saare County, he later served during World War I in the Imperial Russian Navy as an ensign.
Since 1920, Jaan Usin was commander of the Peipsi flotilla in Tartu.
He rose in ranks and was finally, in 1940, promoted to captain, being then commander of one gunboat, one motorboat and 49 men.
He was sunk on board Merikaru in the Väinameri, the Muhu strait.
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