[1] Ao was born in the Longjang village of the district of Mokokchung to Metongchiba Pongen and Melungnenla Imchen on 24 December 1916.
[2] He also served as a primary school teacher in the year 1939 and 1940 at his native village Longjang on monthly salary of Rs 10.
[2] In 1960, Ao resigned from government service and entered politics joining the Naga People's Convention (NPC).
The Convention, established in 1954, however, took a moderate stance calling for the establishment of a separate administrative unit within Assam by merging the Tuensang division of North-East Frontier Agency (NEFA) with the Naga Hills District of Assam.
The Government of India agreed to this demand in 1957, creating the Naga Hills and Tuensang Area.
[5] Ao was part of the NPC team that drafted the resolution and met with Nehru and was one of the signatories of the accord reached between the Nagas and the Indian government.
He lost to the sitting MLA M. Koramoa Jamir of the Naga Nationalist Organisation by 162 votes.
As head of the NPC, Ao enabled Naga politics to adapt to and adopt successfully the Indian parliamentary democratic model of governance, despite problems with insurgent groups continuing.