In 1964, he used his G.I. bill benefits to enroll at the Honolulu Academy of Arts. He began his professional art career at that time, and by 1966, he had attracted the attention of such established artistic luminaries as Madge Tennent, who wrote of Tagami at the time: "I would humbly like to predict that he will be one of the greatest artists these Islands have yet produced." He was the founder and operator of the Botanical Gardens and Gallery on Oahu for several years. In 1998, he teamed up with Michael Powell, another Hawaiian artist, to own and operate Tagami & Powell Fine Art Gallery on the Big Island, in Waimea, at the Kamuela Inn.
A prolific artist who excelled in the palette knife technique, he created over 6000 images over the years. His works are in public and private collections worldwide, including the permanent collections of the AMFAC Corporation, Bank of Hawaii, State Foundation of Culture and the Arts (Hawaii), and the Walter Cecil Rawls Museum in Southampton County, Virginia. Over the years, he instructed some of Hawaii's finest young artistic talent.