In 1845 he was appointed captain of the survey ship HMS Herald, being reassigned in 1848 to join the search for Sir John Franklin. During this voyage he sailed through the Bering Strait across the Chukchi Sea and discovered Herald Island. Kellett landed on Herald Island and named it after his ship. He also sighted Wrangel Island in the western horizon. William Pullen was on this expedition.In 1852, he commanded HMS Resolute and went to the aid of Robert McClure, whose vessel, Investigator, was trapped in the Arctic. His men constructed a storehouse on Dealy Island off the south coast of Melville Island.