Grimmer, currently the managing director of the Publicis-owned media agency Zed Media, will join Nick Hurrell and Neil Dawson to lead the agency's expansion into communications planning and media buying.
He will receive an undisclosed amount of equity in exchange for money he is putting into Hurrell and Dawson and will also have his name above the door. A creative partner is expected to be announced shortly.
Grimmer's appointment forms part of the Hurrell and Dawson strategy of building an agency which integrates creative with media planning and buying. Grimmer will initially focus on building a communications planning team and on moving the agency into buying online and digital media. Buying across other media is expected to follow.
Grimmer joins Hurrell and Dawson after a successful two years as managing director of Zed, during which it has more than doubled its staff and billings numbers. Before that he was group commercial director at ZenithOptimedia and a managing partner at Optimedia.
Hurrell and Dawson, was launched in October 2006 by Hurrell, the former M&C Saatchi Europe chairman and Dawson, the former chairman of TBWA\London. Since then it has hired Shaun McIlrath, a senior creative and founder of Heresy, and Sunita Gloster, the former chief operating officer of M&C Saatchi, to senior roles. Its clients include IPC Media, Auto Trader, and the Red Cross.
Hurrell said: "Greg has a unique set of skills. He is as comfortable talking about TV trading as he is about search engine marketing. With Greg on board, we can now build the type of full service media and creative agency you would build if you were starting from today."
Grimmer was unavailable for comment.