Anna Zalewska was born and comes from Świebodzice in the Lower Silesian Voivodeship. She graduated in Polish studies from the University of Wrocław. She worked as a Polish language teacher and served as deputy director of the General Secondary School in Świebodzice. She is also an education manager and ecologist. She was a member of the Board, councilor and deputy mayor of the Świdnica District.

In the years 2007-2019, she was a member of the Sejm of the Republic of Poland of the 6th, 7th and 8th term. During the 6th term of the Sejm, she worked in the Education, Science and Youth Committee, the European Union Committee and in the permanent subcommittees on the economics of education and science and on the use of European Union funds. She was also a member of the Investigative Committee investigating the circumstances of Barbara Blida's suicide. In the 7th term of the Sejm, she served as a member of the European Union Committee and the Health Committee, also engaging in the work of parliamentary delegations and bilateral groups, including in the Polish-Czech and Polish-Ukrainian Parliamentary Groups. She also supported prosumers in the permanent Subcommittee on Energy.

In 2015, during the 8th term of the Sejm, she took office as the Minister of National Education. During her term, she carried out an education reform, transforming the education system by returning to the model of eight-year primary school. She worked to increase parental involvement in school life and introduced numerous programs supporting educational infrastructure, such as broadband Internet, modern multimedia equipment, laboratories and canteens.

Since 2019, Anna Zalewska has been a Member of the European Parliament, representing Lower Silesia and the Opole region. In the European Parliament, she works in the Committee on the Environment, Public Health and Food Safety and the Committee on Agriculture and Rural Development. She is a member of the Delegation to the Parliamentary Assembly of the EU-UK Partnership. In 2021, she founded and chairs the ECR Carbon Sinks Working Group, focusing on issues related to environmental protection and the fight against climate change.