The new role will see him lead the combined Fallon and Publicis team that manages the Citi brand globally.
Bowles spent ten years at Lowe, rising to the position of managing director in 2001. He quit the agency in May 2004.
He then became the managing partner of WCRS, but left in April 2005 after only six months, having decided not to buy a stake in the agency.
Bowles will be based in the US, where the Citi account is headed out of Fallon's Minneapolis office. The bank has been a client of Fallon's since 1999, and recently handed the agency a global creative brief that sees it partnering Publicis Worldwide to execute local advertising around the world.
"I enjoy working on brands of this scale. Taking a single strategic and creative campaign and launching it around the world is a fascinating challenge," Bowles said.
Bowles' career has also included spells at Saatchi & Saatchi, CDP and Young & Rubicam.