From 2000 to 2002, Medina served as adviser to Prime Minister António Guterres, first on education and science and later on economic policy.

[4] Afterwards, municipal authorities admitted that since 2011 Lisbon’s city hall had regularly disclosed the personal information of human rights activists, including "names, identification numbers, home addresses and telephone numbers", with several repressive regimes, including Angola, China and Venezuela.

Portuguese President Marcelo Rebelo de Sousa described the situation as "deeply regrettable" and declared that everyone deserved to have their fundamental rights respected in a democratic country.

As part of the Tutti Frutti scandal, Medina’s use of influence caused complications to the 2022-2023 Portuguese political crisis, known by numerous cases of corruption within the PS reign.

After the Socialist Party's absolute majority victory in the 2022 Portuguese legislative election, he was sworn in as a member of parliament, and two days later, on March 30, 2022, was appointed Minister of Finance of the XXIII Constitutional Government.