In 2004, he first joined the
European Commission as a civil servant. He went on to serve in a variety of roles, firstly as Commission Spokesperson for Information Society and Media, before becoming head of cabinet to the
Commissioner for Justice, Fundamental Rights and Citizenship,
Viviane Reding. He was appointed by the commission, as a principal adviser to the
Directorate-General for Economic and Financial Affairs, and as a director at the
European Bank for Reconstruction and Development. In early 2014,
Jean-Claude Juncker won the nomination of the
European People's Party (EPP) to be their candidate for
President of the European Commission. Juncker appointed Selmayr his campaign director, and after the EPP emerged as the largest party in the
European Parliament following the
election in May 2014, Selmayr became the head of the Juncker transition team. After taking office as president on 1 November 2014, Juncker made Selmayr his head of cabinet and chief of staff. Shortly after his appointment, various media reports began to profile Selmayr as a highly influential figure within EU politics, with
Politico describing him as "the most powerful EU chief of staff ever" in November 2016, noting that even Jean-Claude Juncker jokingly referred to Selmayr by the nickname "the Monster."
Tomáš Prouza, the
Czech State Secretary for European Affairs, stated publicly that "when I need a decision to be taken...I talk to Martin". In October 2017, he was accused in the British media of leaking details relating to
Brexit negotiations, though Selmayr denied these accusations. In December 2023, the
Financial Times reported that China's
Ministry of State Security had previously targeted Selmayr.
Secretary-General Selmayr was appointed Deputy
Secretary-General of the European Commission in February 2018. Minutes after this appointment, Juncker informed the
European Commissioners that the then secretary-general,
Alexander Italianer, intended to retire; they had not been previously notified of this. On 1 March 2018, following the formal retirement of Italianer, Selmayr was approved by the
College of Commissioners to replace him as secretary-general. Some media sources claimed that support for Selmayr had been "bought", and with others claiming that Selmayr had "forced" his way into the position. The president of the European Commission Jean-Claude Juncker reportedly threatened to resign if the controversy led to Selmayr's dismissal. On 25 March 2018 the commission issued a formal statement claiming that Selmayr's promotion was in accordance with legal procedures. The
European Ombudsman contested the lightning-quick appointment of Selmayr from deputy secretary-general to secretary-general, found instances of "maladministration" and concluded that the commission "did not follow EU law". The Ombudsman's statement was rejected by the commission. In the immediate aftermath of his appointment as secretary-general of the European Commission, it was reported that Selmayr had been editing Wikipedia using his own name from an account using a verified ec.europa.eu email address. The commission stated that he did so to correct specific information (including his work positions as well as political and religious affiliations), "in direct interaction with a Wikipedia editor, who checked and verified all information ...and ensured that it is properly referenced". Selmayr resigned as secretary-general on 1 August 2019, having held the office for less time than any of his predecessors; it was speculated that the decision by the
European Council to nominate
Ursula von der Leyen as replacement for Juncker as commission president was a factor behind the decision. He was subsequently appointed as the EU's permanent representative to
Austria. ==Other activities==