He will work across client business, including supermarket Tesco and restaurant chains Burger King and TGI Fridays, and will report to Chris Wright, head of broadcast at Initiative.
Bentall joins Initiative from MediaCom Direct where he spent seven years and, most recently, worked on the T-Mobile and Great Ormond Street accounts.
He said: "I’m looking forward to bolstering Initiative's client offering, by bringing to life a new era of direct and ROI planning."
Gary Birtles, chief executive at Initiative, said: "Tristan will continue to refine and develop our response offering as it grows, as well as driving additional return on investment for our existing clients."
This article was first published on Media Week