King has been managing director of OgilvyOne London since the beginning of this year.
However, she has worked at the agency for the past eight years, starting with a four-year stint running the Amex 360 EMEA business.
In 2005, King was promoted to client service director, with primary responsibility for new business, and shortly after this she ran the agency's digital arm, Ogilvy Interactive.
King was then promoted in November 2006 to deputy managing director and during 2007 she led the team, which won that year's biggest DM pitch for British Gas.
Prior to her arrival at Ogilvy, she worked for eight years at Wunderman, mostly in New York.
Sam Williams-Thomas, OgilvyOne London's deputy managing director, will replace King as managing director.
Paul O'Donnell, EMEA chairman of OgilvyOne Worldwide, said: "It's always a pleasure to be able to reward talent and loyalty and the promotions of Annette and Sam are an acknowledgement of their excellent records in the fields of new business and account management.
"They'll make a great team as they complement each other perfectly; they also understand the agency, its culture and the client base intimately. Both are true 'internationalists' who have made a significant impact in the UK marketplace."