He has broad experience in a wide variety of real estate transactions, including advising on commercial real estate transactions, controlled auctions of real estate portfolios, sale and lease back transactions, property development (including advising on joint ventures), urban redevelopment and the provision of security in financial transactions. Leon is also a recognised expert in the field of social housing and he advises social housing associations on subjects as compliance, governance, cooperation with third parties and local government as well as real estate related topics. Leon has acted for property developers, owners, investors, local governments, social housing associations, consultants and lenders.

Prior to joining A&O Shearman Leon was a partner at AKD. He is a member of the Vereniging Bouwrecht (construction law association) and the Royal Institution of Chartered Surveyors (RICS).