Easterbrook, who took chief executive officer positions with two other companies during an 18-month break from McDonald's, would be in charge of advertizing and "all the ways customers experience McDonald's," the company said in a statement.
Easterbrook's return follows a month-to-month same-store sales in November -- the company's first such decline in nine years -- the Chicago Tribune reported Saturday.
Market analysts have said McDonald's lacks depth in the executive suite due to the untimely deaths of CEOs in 2004 and 2005, and the departure of several top executives -- including Chief Operating Officer Mike Roberts in 2006, COO Ralph Alvarez in 2009, and the head of European operations Denis Hennequin in 2010.
McDonald's U.S. President Jan Fields resigned in 2012 after 35 years with the company.
"You've seen a number of departures ... (so it) certainly helps to have someone who knows the business being put back in the fold," said market analyst R.J. Hottovy at Morningstar.
"McDonald's does have a strong bench of talented executives who are focused on the Plan to Win and on our three global priorities -- optimizing the menu, modernizing the customer experience and broadening our accessibility to even more customers. We have the right people in the right places and a steady pipeline of future leaders poised to drive the business forward," a company spokeswoman said in a statement.