The post has not been formally occupied since Nik Studzinski, now the Publicis creative chief, was relieved of it in May last year. Now it is to be occupied by Andy Clarke, one of the Saatchis creative partners.
The job disappeared when Granger opted for a flatter departmental structure.
At the time, he said: "I'm an art director and very involved anyway, so a head of art is not entirely necessary."
This week, however, Granger said he was happy to confirm Clarke in the role he had been caretaking for the past few months.
"This isn't a change of heart," he added. "Nik decided he didn't want the job any more and we decided to split the role among a number of art directors. What happens is that one art director tends to take more responsibility and Andy has been our unofficial head of art for a while. He's also my right-hand man."
Meanwhile, the agency has broken with established practice to appoint Paul Domenet as its first head of copy for several years. "He has been an incredible asset on the creative floor for six years through his high-calibre work and dedication," Granger said.
The changes coincide with the appointment of the Bartle Bogle Hegarty creatives Paul Miles and Adam Staples, who join Saatchis in senior roles.
The pair, who both work as art directors and copywriters, joined BBH from Leo Burnett in April 2002. Since then they have worked on Levi's, Audi, Bertolli, Lynx, Sony Ericsson, ITV and Impulse. Their awards haul includes a Campaign Press silver as well as gold, silver and bronze honours at the Creative Circle.