Engine has also hired Paul Jordan to lead WCRS as executive creative director. Jordan will join from Mcgarrybowen where he is joint executive creative director.
Jordan will sit on the WCRS management team alongside chief executive Matt Edwards, managing director Annie Gallimore and chief strategy officer Matt Willifer.
Faithfull started at WCRS in 2005 with former creative partner Ross Neil. They were promoted to joint executive creative directors in 2014.
Neil left WCRS in February and has since moved to McCann London. Leon Jaume remains joint executive creative director at WCRS.
Jordan helped launch Mcgarrybowen in London in 2012 and has worked with clients including Honda and Nike. He was previously a creative director at Wieden & Kennedy London for four years and has worked at Abbott Mead Vickers BBDO, where he was responsible for the Guinness "Tipping point" campaign and ran the agency’s government business.
Faithfull said: "Clients need more magic and integrated thinking than ever before. Engine was conceived with this future in mind so I’m excited about representing and building the creative culture at a group level.
"We’ve been searching the industry from top to bottom for the right person to take on the WCRS role. I’ve been a big fan of Paul’s work for years. Like the best creative people, he mixes a shrewd mind, wide-eyed optimism and integrity."