He is named after his ancestor Kaumuali'i, the last king of Kauai before being ceded to the unified Hawaiian Kingdom governed by Kamehameha the Great. His name means "Born To The Purple" and "Oven Of The Nobility". He is of higher rank than his first-cousin Quentin Kuhio Kawananakoa as his rank is higher maternally, in preference to Hawaiian traditions of genealogy of the chiefs.
He was educated at Punahou School in Honolulu, Hawaii. He works as an art dealer in London and with Marzia Ratti wrote Matteo Sandonà and Hawai‘i: A Capital Ambition, a bibliography of Matteo Sandonà who was known for his sophisticated portraits in oil and on paper.