Ward will be finishing off a Hollywood screenplay and is also understood to be in discussions with other agencies about a new position.
Worley is joining McCann Erickson from the production company Partizan, where he was a senior producer.
In his new role, he will take charge of the entire McCann broadcast output, including Chrome, the agency's digital production facility, and the TV department. Petrina Kilby will stay as head of TV and will be in charge of the day-to-day running of the department.
The McCann joint executive creative director Brian Fraser said: "Stephen will add lots of value and energy in our determination to be one of the best UK agencies in terms of TV production quality, understanding the changing TV technologies and changing media channels we need to exploit for our clients."
Ward was promoted to the position of creative director at EMEA in June to fill the European role originally set for the former McCann executive creative director Robert Campbell before he left.
Worley was the former managing director at the production company Rose Hackney Barber. He left there in 2001 following a difference of opinion over the future direction of the company.