Reis became a member of the Grândola municipal assembly in 2010, serving until 2017. For a time, she was the leader of the PSD group in the assembly. She rejoined the municipal assembly in 2021 and again became leader of the PSD group. In the 2024 national election the PSD formed a coalition with two smaller parties to fight the election, known as the Democratic Alliance. Reis was fourth on the list of AD candidates for the Setúbal district and the coalition won four seats, resulting in her election. In the parliament she was appointed to be a member of the Committee on Agriculture and Food.