He was twice elected Director General of the United Nations Industrial Development Organization (UNIDO, 1997, 2001) by the international community, made up of 178 Member States.

He returned to Argentina in July 2019 to continue his career in the private sector, recruited by Spencer Stuart to lead the Argentine Chamber of Energy.

While studying was elected Academic Counselor by the Student Senate to represent it on the Board of the Faculty of Economic Sciences (FCE UBA), its governing body (1985–87).

He also studied at the International Development Law Institute (Rome, 1990) and specialized in Mergers and Acquisitions at Wharton Business School (University of Pennsylvania, 1997).

Towards the end of 1995 Magariños added responsibilities for Mining to his portfolio and, in mid-1996, was appointed Economic and Trade Representative of Argentina in Washington, D.C., with the rank of Ambassador and State Secretary.

Over those years, under Magariños leadership, UNIDO developed a cooperation framework with the private sector through multinational companies (Fiat, BASF, Erickson, etc.).

[12] He sat on several boards of institutions and organizations in the US, Europe, Asia and Latin America, including University San Ignacio of Loyola, the Council on Energy, Environment and Water (CEEW), the Global Alliance of SMEs, the Bank of the Province of Buenos Aires (board member 2007–2011, appointed by Governor Daniel Scioli), the oldest bank of Argentina, and Circulo of Montevideo.

His interest in understanding the challenges confronting developing and emerging societies in a globalized economy led him to design and manage various research projects.

A combination of personal and professional engagements (recruited by Spencer Stuart to lead the Argentinean Chamber of Energy) drove him back to Argentina in July 2019, to continue his career at the private sector.