Prior to entering politics, Ainuu was a journalist with the Broadcasting Corporation of Niue and a Public Relations and Media Officer with the Niuean government.

[1][2] She was also the president of the Niue Island Volleyball Association and a founding member of the Pacific Alliance of Development Journalists.

[5] She was subsequently appointed Member Assisting the Minister for Natural Resources.

[6] On 11 June Ainu'u was appointed Minister of Natural Resources in the Cabinet of Dalton Tagelagi.

[7] She was re-elected unopposed at the 2023 election,[8] and reappointed to Tagelagi's cabinet holding the same portfolios.