Mattheisen graduated in history at Indiana University, Bloomington (1979–1983) and economics at Columbia University, New York (1986–1988). In 1990 he came to Hungary where he started a consulting company for business analysis and strategic planning. In 1993 he was the founding marketing and sales director of T-Mobile Hungary (formerly Westel 900). He moved on to Poland in 1996 to participate in launching the mobile operator Era GSM for US West International as Director of Marketing, Sales and Strategy. From 1997 he headed in London the marketing and sales activities of US West’s (later MediaOne) European mobile subsidiaries, then from 1999 he worked at BT Cellnet as Business Marketing and Sales Director. In September 2002 he was appointed of Magyar Telekom’s Chief Officer heading the Residential Services business unit and member of the Management Committee. From January 2005 to June 2006 he was Chief Officer responsible for the Wireline Services business unit (T-Com, including the residential, Internet and network divisions). On December 5, 2006 he was appointed CEO of the company and on December 21 elected member and Chairman of the Board of Directors. Under his leadership, Magyar Telekom won a string of professional awards such as Business Ethics Award (1997), Best Employer in Hungary (2009) and in Central and Eastern Europe (2010), and an international Innovation Award (2010).
Important milestones in his professional career