Romerson worked as a barber before his enlistment in 1863. It is thought that he came to the United States as a sailor aboard a merchant or whaling ship in the Pacific; Hawaiian sailors were highly regarded in the 18th- and 19th-century maritime industry and sought out as crew members. Regardless, it is known that Romerson was living in New York prior to joining the Navy. Probably helped by his experience at sea, he enlisted on January 22, 1863, as a landsman in the Union Navy. He served on and as part of the Blockading Squadrons, responsible for maintaining the blockade of the ports of the Confederate States.