Bennett, who has been at Maitland for six years, was previously vice-chairman. He replaces Philip Gawith, who is understood to have left the agency.
Gawith had been at Maitland since 1998, having previously spent nine years as a journalist at the Financial Times. He became chief executive of Maitland in 2008.
Bennett will now spearhead the Havas-owned agency alongside founder and chairman Angus Maitland.
Prior to joining Maitland, Bennett was chief executive of Gavin Anderson UK and City editor of the The Sunday Telegraph for six years.
