Son of a Navy Chaplain, EAF Lavallette first served aboard the Dispatch in the War of 1812 in the Battle of Lake Champlain. He was acting commander of the U.S.S. Constitution for a short while and also served in the Mexican-American War of 1848 as military and civilian governor of Mazatlan. He went on to be commander of the Mediterranean Squadron in the 1840s and the African Squadron in the 1850s for which he was mentioned by Congress. When President Lincoln created the rank of Rear Admiral, he was chosen as one of four commanders to be promoted.