After taking several prizes, he accepted a captain's commission, which he had declined on entering the service, preferring to win it by promotion.

When returning to Buenos Aires in June 1828, his brig, the “Brandsen,” was driven inshore in the Rio Plata by a Brazilian squadron.

He scuttled the vessel to prevent her capture, swam ashore with his crew, and on reaching Buenos Aires was made commodore.

Returning to New York, de Kay married in 1833 Janet, only child of Joseph Rodman Drake, the poet.

In 1847 he took the U. S. frigate Macedonian to Ireland with supplies for the sufferers from the famine, having exerted himself to secure the passage of an act of Congress permitting a government vessel to be so employed.