Leeson will be responsible for integrating processes, practices and tools into Social Chain to help build the grow the company.
After being promoted to her MediaCom role in January 2015, Leeson oversaw marketing strategy and co-ordinated the prospecting strategy, which involved identifying leads and co-ordinating pitches.
Social Chain CEO Steven Bartlett said: “We are absolutely delighted to have Katy on board to help drive the company forward. With business in New York and Berlin booming, and the Manchester office continually growing, Katy will help steer us in the right direction and help us make strategic new business decisions.”
Leeson added: “Social Chain really impressed me with its unique approach. It is such an exciting company and I can’t wait to be part of something that produces incredible pieces of work and results off the back of that energy.
“Social Chain is already such a success story, I want to use my experience to help develop the existing processes and help the business to continue to grow.”