[1] Between 7 November 2014 and May 2016 he served as Deputy Prime-Minister of Bulgaria, and Minister of Labor and Social Policy in the Second Borisov Cabinet.

His foreign language skills include English, French, Russian and Spanish.

Kalfin founded the Social Democrats National Movement and served as the deputy president of the Common Parliamentary Committee Bulgaria-European Union between 1995 and 1998.

He observed the elections in Kosovo in 2001 and 2004 as part of Organization for Security and Co-operation in Europe missions in the region and has also worked as a senior university lecturer and manager in several consulting companies.

We would particularly much insist on the observance of the principles of good-neighbour relations and the lack of aggression towards the Bulgarian nation or history on behalf of the Macedonian authorities.On 28 July 2006 Kalfin appealed to the Skopje authorities to replace the director of the Macedonian cultural and informational centre in Sofia Stefan Vlahov-Mitsov: The Macedonian authorities should clearly prove that it is inadmissible for an official of a diplomatic representation abroad to participate in that country's political life.His statement was provoked by Mitsov's alleged participation in the management of UMO Ilinden-Pirin, a controversial party largely regarded as Macedonist and anti-Bulgarian by the Bulgarian public.