Earlier offices held by Marton-Lefèvre include Executive Director of LEAD (Leadership for Environment and Development) International, a programme established by The Rockefeller Foundation to bring together and train mid-career leaders from all parts of the world in improving their leadership skills around the issues of sustainable development, and Executive Director of the International Council for Science (then known as ICSU).
From 2019 to 2023, she served as an elected member of the Bureau of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) .
Her links with academic institutions are with Yale University, where she spent 2016 as the Edward P. Bass Distinguished Visiting Environmental Scholar.
Marton-Lefèvre's other board memberships include the Wildlife Conservation Society (WCS), the Turkana Basin Institute, and the Oceanographic Institute- Prince Albert 1st of Monaco Foundation.
She has also participated in corporate environmental advisory boards to the Dow Chemical Company, to the Coca-Cola Company, as the Chair of the Independent Advisory Board to the Sustainable Biomass Program, advising seven large energy companies, and as a member of the Critical Friends group of Veolia Environment S.A. Marton-Lefèvre is the recipient of the AAAS Award for International Cooperation in Science;[4] and has been honoured as a Chevalier de la Légion d’Honneur and as an Officier de l'Ordre National de Mérite by the government of France, and as a Chevalier dans l'Ordre de Saint-Charles by Prince Albert of Monaco.