Mark has been using Python since 2005, and has been contributing to CPython since 2010. After a long interlude working on static analysis tools, he has returned to working on speeding up Python over the last couple of years. His academic and commercial work is focused on compilers, virtual machines and static analysis for Python. His Ph.D. was on building virtual machines for dynamic languages. He is the author of various PEPs including 412, 590, 626 and 659.
Mark is currently working as the technical lead of the "Faster CPython" team funded by Microsoft.

After working as an Assistant Professor in the Department of Medical Communication at the University of Tokyo Graduate School of Medicine, Deputy Director of the University Hospital Medical Information Network Research Center, and a visiting researcher at a research institute in Boston, he founded Data Vehicle, Inc. in November 2014. He is engaged in the development and sales of extended analytics tools such as "dataDiver," utilizing his own expertise, as well as supporting public and private sector data utilization projects. His publications include the "Statistics is the most powerful science" series, which has sold over 500,000 copies, and "Statistics Will Save Japan" (Chuokoron Shinsha). He is also a member of the Advisory Board of EBPM (Evidence Based Policy Making) of the Cabinet Office since 2020.