Following the earlier announcement that the Liberal sitting member,
Peter Debnam, would not re-contest the next state election, Upton won Liberal Party pre-selection for Vaucluse on 26 September 2010. At the
2011 state election, she
was elected with a swing of 9.9 points, winning the seat with 81.4 per cent of the
two-party preferred vote. Following the election, she was appointed Parliamentary Secretary for Tertiary Education and Skills. On 21 August 2013, Upton was appointed as the Minister for Sport and Recreation. Due to the resignation of
Barry O'Farrell as premier in April 2014, and the subsequent ministerial reshuffle by the new Liberal Leader,
Mike Baird, Following the
2015 state election, Baird announced that Upton would be Attorney General, becoming the first female
Attorney General of New South Wales. As Attorney General, Upton introduced a pilot program to help support child witnesses through the court process, using specialist judges to better deal with child sexual assault trials, and experts called "children's champions".
Minister for the Environment, Local Government and Heritage Following the resignation of Mike Baird as Premier,
Gladys Berejiklian was elected
Liberal leader and sworn in as Premier. Upton became the Minister for the Environment, the Minister for Local Government, and the Minister for Heritage in the
Berejiklian ministry. In response, the Chair of the Save Our Sirius Foundation noted that her determination was "an ignorant decision made by an out-of-touch government [...] Upton's only argument and the only thing she cites in her decision is the opinion of a group of private companies the government hired to tell them what they want to hear." In December 2017, Upton introduced the
container deposit scheme called "Return and Earn". It was the single largest initiative undertaken to reduce litter in NSW, and was associated with a 28% drop in litter covered by the container deposit scheme in 2017–18, compared with 2016–17. In May 2018, together with the Premier, Upton announced the $45 Million Koala Strategy, the largest commitment by any state government to increasing the
koala population. The package included additional natural habitat for koalas, funding to tackle diseases, improve research and address roadkill hotspots. In September 2018, a number of concerns were made public over Upton's ability to perform as a minister. Allegations from former staff and other government sources included her "contempt for bureaucrats", suggestions that she was "paralysed by indecision", and claims that "Departmental briefs sat on her desk for months and months without her even looking at them". The month before, Upton came under fire for allowing a significant delay in determining applications for new items to the
New South Wales State Heritage Register, with the exception of
Hadley Park in
Castlereagh, the original home of the family of conservative radio commentator
Ray Hadley, thereby fulfilling her obligations under the
Heritage Act 1977 "almost entirely in the breach". Attention also focused on the "toxic environment" of her 12-staff office, with 16 staff members having left in the 18-month period up to September 2018, and one former staffer receiving compensation for severe stress. Upton was not reappointed to the ministry following the
2019 state election. ==Later political career==