Details are vague at the moment, but we’ve received confirmation that Leo Burnett chief strategy officer Stephen Hahn-Griffiths, who works out of the Chicago office, is now leaving the agency. Leo Burnett would not comment further on the matter, but what we do know is Hahn-Griffiths joined the agency 18 months ago from Mullen, where he also held the title of CSO as well as managing partner. He was eventually replaced a month later at the latter agency by Kristin Cavallo.

Hahn-Griffiths had spent two-a-half years in all at Mullen, initially joining as EVP, director of bland planning before eventually moving up to the CSO post. While at Mullen, he helped the agency win creative accounts for the likes of  JetBlue and Zappos among other achievements. During his career, the exec has held many gigs on the strategy/planning side, including an eight-year stint at Doner. We’ll let you know if and when we find out where he’s headed to next.