Following the end of World War II Gardeniers-Berendsen worked as a secretary in Rotterdam from August 1945 until May 1971.

After the election of 1977 Gardeniers-Berendsen was appointed as Minister of Culture, Recreation and Social Work in the Cabinet Van Agt–Wiegel, taking office on 19 December 1977.

After the election of 1981 Gardeniers-Berendsen returned as a Member of the House of Representatives, taking office on 10 June 1981.

The Cabinet Van Agt II fell just seven months into its term on 12 May 1982 and continued to serve in a demissionary capacity until it was replaced by the caretaker Cabinet Van Agt III with Gardeniers-Berendsen continuing as Minister of Health and Environment, taking office on 29 May 1982.

After the election of 1982 Gardeniers-Berendsen again returned as a Member of the House of Representatives, taking office on 21 September 1982.