William L. Mosseray

William Mosseray is a senior European business leader, advisor and executive coach. He is a Partner (part-time) at SEEWHY Partners in Brussels, where he supports Boards on governance and human capital matters, including board evaluation, board director search, board advisory, and family business advisory. He is also President and Founder of LONGVIEW SAS in Paris, a transformation and leadership advisory firm, where he advises CEOs, CHROs, and executive teams, as well as professional investors, on executive talent acquisition, assessment and development, leadership coaching, team dynamics, and organizational design in the context of major transformations.

Before founding LONGVIEW, William served as Vice-President Strategic Group Resourcing at ENGIE Group and was a member of the Group HR executive team. In that capacity, he helped build and scale global executive sourcing, assessment, and development capabilities to support ENGIE's worldwide transformation agenda, including setting up an in-house executive recruitment agency, designing executive assessment methodologies for succession planning for top leadership roles, and coaching senior executives on leadership and organization choices.

Earlier in his career, he was a Partner at Eric Salmon & Partners, holding Managing Partner responsibilities in Brussels and London and co-leading the firm's global Leadership Advisory practice. Prior to his advisory work, he held multiple executive committee roles at Proximus Group (Belgacom), including Chief Human Resources Officer, Chief Restructuring & Change Officer, and Executive Vice-President Strategy, and later served as CEO of Telindus International, leading a multi-country ICT business with significant P&L and people responsibilities. He began his career as a senior associate in the Corporate and Tax Department at Allen & Overy in Brussels and Zürich.

A Belgian national and French resident, William has lived and worked in Belgium, Switzerland, the United States, and France. He has completed executive education at Stanford and Kellogg, earned an executive coaching certification at HEC Paris, and holds law and business degrees from KULeuven, UNamur and Vlerick. He also serves in various board and advisory capacities, including as Chairman of the Remuneration Committee of Touring Club of Belgium, as well as nonprofit and supervisory board roles. Fluent in French, English and Dutch, William's personal interests include world affairs, education, travel, contemporary art, and hiking.