Mitchener brings more than 30 years of media and PR experience and most recently has been an independent strategic communications adviser.
He takes over from the founder of the Brussels office, which was set up as Policy Action in 1999 before being acquired by Instinctif a decade ago.
Prior to this he was the CEO of the European Business Aviation Association in Brussels and has also held senior comms roles at Monsato – which is known for genetically modified agriculture – and solar power company First Solar.
He has also worked as a director at APCO Europe and previously had a distinguished journalism career working for mastheads including the Wall Street Journal, The International Herald Tribune and Dow Jones Newswires.
"I’m humbled to have been selected to lead Instinctif’s Brussels office," Mitchener said.
"I remember the days when Wes and Lucy Cronin [managing partner of Instinctif’s Dublin Office] lobbied me on the EU Copyright Directive when I was still a journalist at The Wall Street Journal. I developed a respect for them both then that helped make it easy to join Instinctif today."
Instinctif’s public policy practice senior managing partner Warwick Smith added: "Wes’ contribution to the Brussels office and the company as a whole has been enormous. Filling his shoes will be no easy task.
"We are delighted that someone with the experience and distinguished career that Brandon brings to the party is joining us. We look forward to further positive developments of Instinctif Partners’ offer in Europe."
Recently, Instinctif Partners CEO Richard Nichols left his role to become deputy chairman following Tim Linacre's promotion to group MD.