He will head the German operation, alongside senior associate partner Christine Graeff, who helped found and lead the six-strong office.
Weyand takes the role after three years at GA in Germany, prior to which he spent four years at Dewe Rogerson in London handling European transaction work.
GA said it is recruiting to replace Weyand as MD. It is believed around three candidates are being considered. Marketing manager Joanna Trezise said the agency hopes to make an announcement in a few weeks.
The consultancy's Frankfurt CEO Michael Kruesmann is overseeing the office while recruitment takes place.