Björn Wahlroos have an M.Sc. (1975) and a D.Sc. (1979) from the Hanken School of Economics in Helsinki. The following years were spent in academia; as an acting professor of economics at the Hanken School of Economics in Helsinki and as a visiting professor at Brown University and the Kellogg School of Management at Northwestern University, Illinois, United States.
In 1985 Wahlroos switched career to banking, joining the executive board of Union Bank of Finland (Suomen Yhdyspankki). In 1988 he was appointed Executive vice president and Head of Investment Banking & Treasury at the Union Bank of Finland. Together with half a dozen of his colleagues Wahlroos bought out the investment banking operations of UBF in 1992 and started the partnership Mandatum & Co, which soon became the leading advisor of mergers and acquisitions in Scandinavia. Through a merger with Interbank in 1998 Mandatum was listed on the Helsinki Stock Exchange.
In 2000 Wahlroos merged his banking group into Sampo-Leonia and took over as President and CEO of the combined company, also becoming its biggest private shareholder. In 2009 Wahlroos resigned as CEO and was elected Chairman of Sampo plc, holding company of Sampo Group, which by then had become the biggest insurer in Northern Europe and also the main shareholder of Nordea, the region’s largest bank. In March 2011 he was elected as the Chairman of Nordea.
Wahlroos is also Chairman of the Board of UPM-Kymmene, the pulp and paper manufacturer. In the Finnish Defence Forces, Wahlroos holds the rank of Major in the reserves.