In the Fall of 2020, Bouchard announced she was going to run for mayor of Saint-Jean-sur-Richelieu in the 2021 municipal election, and would form a municipal political party in the process. She stated that she wanted to focus on services to citizens and the management of public finances and a new conservation plan.[5] On election day, Bouchard defeated incumbent mayor Alain Laplante by 8,861 votes, winning 64 per cent of the vote in the process. In addition to herself, her party (Équipe Andrée Bouchard) saw 11 of its 12 candidates elected to city council. She became the first female mayor of the city, and also saw the election of a majority female council. Laplante's party did not win any seats.[6] One of the themes of the election was the debate between economic growth and environmental preservation. Laplante campaigned on being a 'defender of the environment', and wanted to protect agricultural land in the city from urban sprawl. Bouchard supported talking to developers, and stated the city had been 'stagnating ... as if economic development has stopped'. She supported attracting businesses and industries, and developing the Saint-Jean Airport area.[7]
As mayor, she had to deal with a water pipe break in the city which deprived half the population of running water.[8] On November 29, 2023, she declared a local state of emergency due to the rupture.[9] She has also been involved in negotiations to bring the Réseau express métropolitain (REM) to the city.[10]
Since her election, she has faced several members of her party quitting to become independents on council to the point where her party now has a minority of seats. It has been seen that her party was more of a coalition built to defeat the previous mayor's administration rather than one built to cohesively run the city. The first defection cam in July 2022 when François Roy left he party citing a difference in vision in the city's development.[11] Councillor Jessica Racine-Lehoux left the party in January 2024 after pornographic video featuring her had circulated.[12] In May 2024, Jean Fontaine was expelled from the party following disagreements between him and the mayor.[13] Later in the month, Mélanie Dufresne left the party after criticizing the mayor and her team for not consulting elected officials on decisions.[14] The next month, two more councillors left the party. First, Jérémie Meunier left, citing a lack of leadership and vision with the Bouchard administration as well as policy disagreements.[15] A few days later, Claire Charbonneau left the party citing similar reasons and a lack of economic development.[16]