In 2013, Tapsell was elected to the Rotorua Lakes District Council[3] and served as Chairperson of the Council's Operations and Monitoring Committee. At 21, she was the youngest councillor ever elected,[4] until the election of 19 year old Fisher Wang in 2019.[8] In 2016 and 2019 she was re-elected as the highest polling candidate.[9]
She voted against the adoption of Māori wards in 2021, arguing that while some councils may need them to ensure representation, Rotorua did not.[10]
On 10 May 2022, Tapsell announced that she would run for mayor of Rotorua.[1] Tapsell announced she would name fellow Councillor Sandra Kai Fong as deputy mayor if both are elected to the council in the October local election.[19] Tapsell campaigned on stopping the spend, combating crime and vandalism, and restoring the city's image as a tourist destination.[1][19]
On 8 October, Tapsell was elected as Mayor, becoming the first Māori woman to be elected as Mayor of Rotorua.[2] She defeated fellow mayoral candidate Ben Sandford by almost 3,300 votes. She and her fellow councillors were sworn into office on 22 October.[20]
In her first year as Mayor, Tapsell turned around a $5.6 million deficit and adopted an Annual Plan that stopped unnecessary spending and made investment in critical infrastructure a priority.[21] To help solve issues in the Rotorua community, Tapsell delivered an exit plan from emergency housing by signing a Rotorua Housing Accord with Central Government which reduced the use of Rotorua motels for emergency housing by around half and ensured more homes were being built for locals.[22] Within a month of being elected, Tapsell put forward a motion to reverse a decision of the previous Council to revoke the reserve status of seven Rotorua reserve sites for development. This was supported unanimously by the Council.[23] To address community safety concerns in Rotorua, Tapsell advocated for an Inner City Community Safety Hub and officially opened this in November 2023 in partnership with Police.[24] In August 2023, following community feedback, Tapsell and Councillors also voted to restore and reopen the Rotorua Museum - Te Whare Taonga o Te Arawa.[25]
In 2023, Tapsell was recognized in the New Zealand Herald's feature on the 130th anniversary of Women’s Suffrage as one of the most influential women in today’s society.[26]
In mid February 2023, Tapsell and the majority of the Rotorua Lakes Council voted to progress a submissions policy that would allow the Council to reject public submissions that were deemed offensive, discriminatory or contained personal threats. Tapsell said that there had been a significant increase in offensive submissions. The submissions policy was criticised by Councillors Robert Lee, Conan O'Brien and Don Patterson on free speech grounds. In response, the New Zealand Free Speech Union warned that it would take legal action against the Council.
Tapsell married Kanin Clancy on 1 December 2020.[27] With him she has a stepson named Kaiarahi. On 10 March 2023, Tapsell announced that they were expecting a baby girl in June. On 2 June she gave birth to Kahumoa at Rotorua Hospital, making her the second mayor in New Zealand to give birth while in office.[28][29]