Her departure follows that of the division's chief executive Christine Costello, who left last month.
Out of Home's two businesses, poster company Primesight and cinema sales house Pearl & Dean, will now handle their own marketing.
Jackie Colvin has been made head of research and consumer insight at Pearl & Dean, and Ian McNaught will handle trade marketing and website development for the cinema business. Both were previously part of the Out of Home marketing division.
New appointments have not yet been announced at Primesight.
Kathryn Jacob, managing director of SMG's cross media sales division, SMG Access, has moved over to become acting chief executive of the cinema arm, while Naren Patel, managing director of Primesight, has become chief executive of outdoor.
Announcing the restructure last month, SMG chief executive Andrew Flanagan said Out of Home's over-arching role did not fit with the company's business model.