Known in early life as Edward James Te Aika Tregerthen, he was the first Rātana Member of Parliament and was elected in a by-election for Southern Maori in June 1932 after the death of Tuiti Makitanara.

He served three years with the New Zealand Māori (Pioneer) Battalion, reaching the rank of sergeant and commended for carrying a wounded soldier while under fire.

During the Second World War in 1944 their second son, Sergeant Pilot John Aperehama, aged 21, was killed in an aircraft accident in Auckland.

Te Mangai persuaded him to stay, and with his practical skills, served the movement by taking charge of harvesting of the Ratana lands.

From his maiden speech, Tirikatene made recognition of the Treaty of Waitangi one of his major aims, presenting a petition with over 30,000 signatures.

The petition from the Ratana morehu was held over for thirteen years before being virtually ignored, but Tirikatane continued to raise the Treaty issue in debates.

During the depression of that time, Māori were expected to subsist from their land, and were not given equal access to unemployment payments and relief work.