Credle, who is Leo Burnett’s US chief creative officer, will join FCB in January 2016. She will replace Jonathan Harries, who has been FCB’s global chief creative officer since 2006.
Harries and Carter Murray, the agency’s worldwide chief executive, have been searching for Harries’ successor for a year.
Murray said in a statement: "The moment we met Susan, we both felt that she would be the perfect creative leader, given our ambition of being a true creative/business partner to our clients to help change consumers’ behaviour."
Once Credle takes on the new position, Harries will become chairman of the FCB network.
"The chairman title and role, at its best, should be held by someone with stature who commands respect in a company. I can think of no one who deserves that title more," added Murray.
Credle began her career at BBDO New York in 1985. She relocated to Chicago for the Leo Burnett job and will return to New York for her new job at FCB. Credle is part of the jury that will give the first Glass Lions, an award for challenging gender bias, at Cannes later this month.
She said: "I believe what we do in the advertising industry makes a difference.
"And, I have learned that for us to make a difference, three elements must be present. People, place and purpose. These are the three reasons I am now joining FCB as part of the global leadership team.
"I respect legacy brands and that includes agencies. In March of 2014, FCB reclaimed its name. It’s a name that has a rich history of creating compelling work that has moved the industry forward.
"Today, FCB has the ambition and the scale to do this again."