The COO post at McDonald's is traditionally seen as a proving ground for candidates for the company's top job.
Fenton, 54, will succeed COO Don Thompson, who will become McDonald's president and chief executive on July 1, following the retirement of current CEO Jim Skinner.
McDonald's said that both Skinner and Thompson recommended Fenton for the COO position.
In his nearly 40-year career with McDonald's, Fenton has held leadership roles in Europe, the United States and APMEA, McDonald's said.
Shares of McDonald's were down 0.5 percent at $96.48 on the New York Stock Exchange.
(Reporting By Lisa Baertlein in Los Angeles; Editing by Bernard Orr)