From March 1991 until June 1992, Mammadov served as a Senior Adviser at the Department of International Affairs at the City Council of Baku, Azerbaijan.

[citation needed] From 2000 until 2006, Mammadov was the Head of the Permanent Representation of the Republic of Azerbaijan to the European Union with an office in Brussels.

He also was a Chair of the Rapporteur Group on Education, Culture, Sport, Youth, and Environment of the Committee of Ministers of the Council of Europe and from 2010 to 2012 a Member of the Governing Board of European Wergeland Center.

[2][3] As of 2019, he directed his efforts, first of all, to establishing strong political and economic relations with the European Union and cooperating in the field of human rights, humanitarian aid, inter-cultural and inter-religious dialogue, combating terrorism and islamophobia.

[8][9] In August 2015 the National Central Bureau of Interpol in the Republic of Azerbaijan issued an international warrant for Mammadov's arrest on corruption charges.

[12] In 2018, Mammadov became a key witness in the investigation of allegations of corruption in PACE[13] in the aftermath of the "Caviar Diplomacy" report by the European Stability Initiative.