[11] Schwartz reportedly played an important role in the beginnings of Aguirre's political career: in 1983, he was the one to convince her, by then a civil servant; to stand as candidate in the Madrid local elections running in the list of the political alliance between Schwartz's Liberal Union, the People's Alliance and the People's Democratic Party.

[12] While in opposition, she was a member of the Standing Committee of the Madrid City Council, a CP spokeswoman on the areas of Culture, Education, Youth and Sports Affairs, and the Moncloa-Aravaca district.

She was subsequently re-elected to the city council and continued in opposition until 1989, when a successful vote of no confidence ousted the PSOE mayor Juan Barranco, which allowed the PP and Democratic and Social Centre (CDS) to govern Madrid for the first time since the restoration of competitive municipal elections in 1979, under the Mayorship of Agustín Rodríguez Sahagún (CDS).

The PP won a council majority in the 1991 election and José María Álvarez del Manzano was subsequently invested as new mayor, with Aguirre remaining in the municipal government board.

were the reduction of surgery waiting times, the building of eight new hospitals and 87 new state schools (most of them bilingual), an increase in the investment for several scholarships of education, and the expansion of the Underground to suburban areas such as Pozuelo de Alarcón.

[15] Aguirre announced her retirement as president on 17 September 2012, citing health issues, and that she would return to her career as a civil servant at the Ministry of Tourism.

[20] In 2016, Aguirre resigned from her position as regional party president, ostensibly due to the many corruption cases in the Madrilenian PP under her watch.

She retained her position of opposition leader in the Madrid municipal government, and the overall maneuver was widely interpreted as a broadside against her party rival, Prime Minister Mariano Rajoy.

[21] On 24 April 2017, she resigned as municipal councillor (and from all relating offices) after the imprisonment of her former right-hand man, Ignacio González (also her successor as regional president) for misappropriation of public funds in the Lezo corruption scandal.

[23] Following an August 2019 request filed by the Prosecution service of the Audiencia Nacional before the instructing judge Manuel García-Castellón,[24] the former charged Aguirre (along with her successors in the presidency of the Madrid region, Ignacio González and Cristina Cifuentes)[25] with alleged crimes of illicit funding, diversion of public money and document forgery on 2 September 2019 in the proceedings of the Púnica corruption case.

García-Castellón, pointed out on a tentative basis the alleged "decisive and essential" role of Aguirre in the PP's illegal funding scheme, through which more than 6 million euros were subtracted from 8 regional ministries and agencies.

[31] According to Jorge del Palacio, Aguirre aimed to develop a Spanish version of the uneasy union between conservatism and the liberalism inspired by Friederich Hayek.