Born as the only child to Akaruke and Puna, he helped raise his wife's children.

He started his professional life as a government radio operator (1939–1954).

In 1955 he became a shipping clerk which he remained until 1963[2] Tangaroa was elected in 1958 to the country's first Legislative Assembly, and subsequently served as member for Penrhyn in the Parliament of the Cook Islands until 1983.

In 1969 to 1970, he was the leader of the now-defunct United Cook Islanders party.

The Cook Islands government website points out that in 2003 he "has the distinction of being the only Cook Islander to have been knighted by Queen Elizabeth II at Buckingham Palace".