A prisoner of war in Germany after his capture in Greece, he returned to New Zealand to finish his university studies and became an accountant.

His alma mater, Victoria University of Wellington, awarded him an honorary doctorate (LLD) for his legal knowledge in 1979.

[5] Ngata received his education at Waiomatatini School, Te Aute College, and Victoria University of Wellington.

On 29 April 1941, he was part of the large group of Māori Battalion soldiers captured by German forces.

After his father's second wife died in May 1948,[10] they took her mokopuna (either a grandchild or grand-niece) Wikitoria ("Wiki") Whyte as an 11-year-old who had until then been raised by them.

[1] Ngata worked as an accountant, first for Gisborne Sheep Farmers and then for McCullochs, Butler, & Spence.

For a time, he was a member of the Gisborne Regional Committee of the New Zealand Historic Places Trust.

A forceful speaker, he was able to interpret and explain impact of legislation on Māori land ownership.

He was one of five candidates who stood for selection in the Eastern Maori electorate for the 1954 election, but was defeated by Claude Anaru, the deputy-mayor of Rotorua.

For the 1969 election, he was their candidate for Eastern Maori but was defeated by the Labour Party incumbent, Paraone Reweti.

In the 1967 Birthday Honours, Ngata was appointed Officer of the Most Excellent Order of the British Empire (OBE) for services to the Māori people.