Weigel, 36, was senior partner, brand planning director at JWT in New York for nearly four years. He led strategy development for United Distillers & Vintners and Unilever brands that included Lipton Brisk.
The new position was created by the New York-based shop's president and founder, Adam Stagliano, who oversaw planning himself for the past seven years.
With increasing responsibilities at global partner Weiss Stagliano O'Malley Hogan International Brand Architecture in Dublin, Ireland, Stagliano said he did not want to work two full-time jobs any longer.
Weigel's arrival in January brings a "true management group to the agency," Stagliano said. "Martin will have an agencywide management role and lead strategic efforts for the entire agency."
Prior to his tenure at JWT, Weigel served as an account planner at the former Lowe Howard-Spink in London for three years.
"After seven years in large agencies, I wanted to try something different," Weigel said. "I find [Weiss Stagliano] a stimulating and entertaining place to work in. It's always been recognized as a very smart agency, one that embraces the value of planning."