Serafin began his professional career at the Office of the Committee for European Integration (UKIE) in 1998. In 2004 he became director of the Analysis and Strategy Department. Between 16 January 2008 and 31 December 2009, he was Undersecretary of State at UKIE and National Aid Coordinator for the Phare and Transition Facility programmes. Following the merging of UKIE and the Ministry of Foreign Affairs in 2010, he was appointed Undersecretary of State at MFA.[2]
From 13 December 2023 to October 2024, Serafin served as the acting Permanent Representative of Poland to the European Union.[5] In August 2024, he was nominated by the Polish Government to be Poland's next European Commissioner.[6]