The appointment is the agency's first major hire since Andrew McGuinness, who took the helm earlier this year.
The newly created role at Freuds means Brooks-Dutton will work across the agency's clients, which include Mars, Pepsi, Public Health England and Diageo.
Brooks-Dutton first joined Mischief in 2008 as creative director after four years at Lexis.
He took up the role of director at The Red Consultancy in 2010 and returned to Mischief in 2012 as managing director.
Since leaving Mischief last year he has been freelancing as a PR ghostwriter.
McGuinness said: "Ben has the pedigree and talent to reinforce our reputation for generating breakthrough ideas. He's a class act."