Mitchell has a background in regeneration and urban theory. He has an MA from the University of Cambridge and MSc and PhD in advanced architectural studies from the Bartlett, UCL. He spent five years at Jones Lang LaSalle in its strategic consulting and development and asset strategy teams, where he worked on large development and regeneration projects for public and private sector clients, including two years on secondment to English Partnerships, now Homes England. He founded Bywater with Richard Walker and leads on project delivery, overall creative direction and environmental and social impact. He participates in a number of industry-wide initiatives relating to the use of mass timber and social impact.