Gregory Then earned a Bachelor of Arts in Human Geography and International Relations from the University of British Columbia before graduating with a Master of Architecture from the University of Toronto in 2018. At the University of Toronto, Gregory was recognized as a John and Myrna Daniels Scholar and received the Jeffrey A. Stinson Graduate Student Endowment Fund for his thesis research, alongside his role as a Graduate Teaching Assistant. His professional experience includes working at the studio of Harry Gugger and Christ & Gantenbein in Basel and Thomas Kroeger Architekten in Berlin, before joining Sauerbruch Hutton in 2020.

At Sauerbruch Hutton, Gregory specializes in leading competitions and projects in early design phases for a range of typologies and programs, including public and cultural buildings, housing, and re-use projects. He plays a key role in pushing the design agenda at Sauerbruch Hutton by fostering innovation in these initial stages. Gregory was appointed an Associate in 2025.