He will replace Chris Hunton, who resigned last week without a job to go to.
As part of the changes, instituted by the agency's recently installed chairman, Rupert Howell, Euro RSCG London's new-business director, Christian Hinchcliffe, has been hired as the marketing director.
Whyte will take up his new job on 1 May. He moves across from McCann's European operation, where he has been the client services director since the end of 2002.
Whyte said: "Joining the new leadership team at McCann London is a fantastic opportunity and one that I relish. I'm confident that we can restore the agency to its former glory. The client list is extraordinary and we are going to raise our game to meet their growing needs,"
Whyte's advertising career began in 1985 at Abbott Mead Vickers BBDO.
Following stints as Leagas Delaney, Still Price Lintas and GGT Advertising, he joined Leo Burnett as the managing director, rising to chief executive in 2001.
However, he was fired from the agency by its former worldwide chief executive, Steve Gatfield, in March 2002 and replaced by the agency's current group chief executive, Bruce Haines.
Hinchcliffe, who will report to Whyte, will be responsible for new business and business development at the London agency, as well as co-ordinating new business at McCann WorldGroup.
Howell said: "I decided we needed someone in this overarching role and asked a number of consultants who they considered to be the best in the business. Christian was on all their lists, so I am delighted that we have been able to entice him to join the new McCann - and I owe them lunch for saving me a headhunter's fee."
The changes come as McCann goes through a turbulent period of account losses. This week it decided to pull out of the pitch for the £11 million Norwich Union account, on which it is the incumbent. This follows losses including Birds Eye frozen foods, Greene King and Glenfiddich.
Howell and McCann's executive creative director, Robert Campbell, have been working on overhauling the agency, in an attempt to stop the stream of account losses. Last month, they won their first pitch together for the Signet Group, the owner of H Samuel and Ernest Jones.