Graduated in biology and environnemental law, Bernard Cressens began his professional carreer in agriculture. He founded the Conservatoire d'Espaces Naturels (Natural Areas Conservation Society) of Isère, a French Department of the Alpine Region, that he has managed for 12 years. He worked as a consultant in New Caledonia for the North Province and in French Polynesia on environmental projets.
WWF France recruited him for his office in French Guyana and then at its national headquarters as Director of conservation programmes. He is a municipal councillor, an administrator of several environnemental NGOs, and the president of the Marine Natural Park of the « Glorieuses » islands (French territory in the Indian ocean).
The Council of the IUCN French Committee, that brings together 8 publics bodies, 42 NGOs and 2 ministries , has elected him as Chair since the 9 April 2014.