Affleck was a managing partner at Vizeum UK before moving to a global innovation role and then to president of Vizeum US in 2016 at the time it became a business unit within sister shop 360i.
At Fetch he is tasked with attracting digital economy brands and will report to Matthew Platts, head of Dentsu Aegis Media Brands UK & Ireland, on UK responsibilities and Fetch executive chairman James Connelly and chief operating officer Greg Grimmer on global matters.
Connelly, who founded Fetch and sold it to Dentsu Aegis in 2014, moved to the role of executive chairman from that of chief executive earlier this year.
Affleck takes over the management of Fetch UK from Jo Sutherland, who was managing director before being promoted to head Carat in April.
Dentsu Aegis credits Affleck with leading 360i’s media practice’s adoption of a more data-centric approach to planning and activation, resulting in a number of new business wins such as Shiseido, Hudson Bay and Sonos.
Platts said: "Patrick's experience and recent success has seen him become well-recognised across our network as one of our most creative and entrepreneurial thinkers."
Fetch UK employs around 100 staff in Shoreditch and works for clients such as Facebook, Shop Direct and The Telegraph.