Jozef De Mey started his career in 1967 at the Insurance Control Authorities of Ministry of Economic Affairs. From 1969 until 1971 he worked at Kredietbank Belgium. In 1971 he joined John Hancock, a financial services provider, where he held various positions untill he joined Fortis in 1990. At Fortis Jozef De Mey served as general manager of Fortis International, CEO of Fortis AG and was appointed member of the Executive Committee in September 2000 where he was responsible for the Belgian and international insurance activities.In 2007 he was appointed Chief Investment Officer within the Executive Committee. Jozef De Mey left Fortis in December 2007.

As of January 2008 Jozef De Mey holds the following board memberships: Fortis Bank NV, Fortis Insurance N.V., Fortis Insurance International N.V., Fortis Insurance Netherlands N.V., Fortis Insurance Belgium NV, and Geneva Association.