On 23 May 2002, Van Vroonhoven entered the Dutch House of Representatives. She was a tax spokesperson and was involved in cultural policy and starting entrepreneurs. Between 13 May and 17 August 2008, she was temporarily replaced as Member of Parliament by Ine Aasted-Madsen [nl]. She was not a candidate in the 2010 Dutch general election so her membership of the House ended on 17 June 2010. Between 11 March 2010, and the end of 2011 she sat for the CDA in the municipal council of The Hague.
From 7 May 2014 to 17 December 2017, Van Vroonhoven was an alderman in the municipality of Hilversum. Her portfolio included housing and land affairs, nature, environment and sustainability and historic preservation. She resigned from her position on 17 December 2017; her husband had found a job in Melbourne, Australia and the entire Van Vroonhoven family emigrated with them.
Van Vroonhoven returned to the Netherlands in 2022. She helped Omtzigt establish the New Social Contract (NSC) party in the summer of 2023, and she canceled her CDA membership. She became an employee of NSC and served as a spokesperson. Placed second on the party list, she was elected in the 2023 Dutch general election, and she returned to the parliament after more than a decade.[1][2][3] Van Vroonhoven is the NSC's vice parliamentary leader and its spokesperson for justice, security, culture, and labor market.[1][4] She assisted Pieter Omtzigt and Eddy van Hijum in formation talks for theSchoof cabinet, and the NRC newspaper described Van Vroonhoven as Omtzigt's emotional support.[5] She took over Omtzigt's responsibilities in September 2024 debates on the 2025 Netherlands budget after he announced his temporary retreat.[6]
Underline signifies the parliamentary leader (first mentioned) and the Speaker Angle brackets signify a replacement member or a member who prematurely left this House of Representatives