During his five years at EHS Brann, Culshaw was the head planner on the agency's flagship Tesco business, for which he won a Marketing Society Award. He also won a titanium Lion at Cannes in 2005 for his work on Volvo.
Before that, Culshaw was the planning director at Y&R/Wunderman, where he worked on accounts including the AA, Vodafone, Xerox and Sony Ericsson.
John Hiney, Carlson's managing director, said: "Guy's skills across all communication channels and disciplines rest well with the customer journey approach we take."
Culshaw's appointment follows that of the creative director, Mark Attrill, who also joined Carlson from EHS Brann, in April.