Maas has a M. Sc, from Wageningen University, the Netherlands.

He has served in diplomatic, management and consulting positions, including: Agricultural Attaché in Dutch Embassies in Europe, the Middle East and Asia, director of a Dutch business organization, consultant for the Dutch Ministry of Foreign Affairs in the West Bank and Gaza Strip, director of the World Food Program in Rome, and policy advisor to governments of the former Soviet states in Central Asia.

Maas chairs the Village Assistance Program (VAP), is a Great Decisions group leader, and assists with the Model UN.