She retired after three terms, having been very popular. She successfully attempted a political comeback, standing in the 2013 local elections in the Riccarton-Wigram ward as councillor for Christchurch City Council, being returned with the highest number of votes across all city wards. She subsequently accepted the role of deputy mayor.
Buck was first elected to Christchurch City Council in a by-election in May 1975 standing for the Labour Party at the age of 19, which made her the youngest city councillor in New Zealand at the time.
Despite her youth, she soon made an impact around the council table and attracted the attention of news media. She was one of five Local Government Commissioners working from 1984 to 1989 on a major reorganisation of local government in New Zealand.
Buck became the city"s first woman mayor in 1989. She stood for mayor as an independent.
An active and vigorous leader, she is widely credited with leading a turnaround in the perception of Christchurch as a city.
Her sister Sally Buck had been an elected councillor for Christchurch City Council since 1998, but retired from the city council in October 2013 after five terms. More recently she has:
been chair of the New Zealand Learning Discovery Trust, which in turn has set up Discovery 1 and Unlimited state schools in central Christchurch. The schools are based on the student being central in their own individual learning
initiated the LIFT Trust with five schools in Linwood to create free tertiary education for studentswho may otherwise not enjoy this because of the fees barrier. been on the New Zealand advisory board of Craigmore Sustainables, involved in carbon forestry.
In 2008 she was nominated by a panel commissioned by The Guardian newspaper as one of 50 people who could reverse the effects of climate change.
Buck stood as an independent candidate in the 2013 local elections in the Riccarton-Wigram ward as councillor for Christchurch City Council. She supported Lianne Dalziel"s mayoral campaign, although initially declined to become deputy mayor.
On 12 October 2013, Buck was returned with the highest number of votes of any of the council candidates across the city. In late October, Buck changed her mind and decided to accept the role of deputy mayor after the role having been re-framed to not just include ceremonial duties.