Easterbrook writes in an email to staff that he had a love relationship with an employee of the company and that it was a mistake. The company's policy does not allow managers to have relationships with employees.
The board has already appointed Chris Kempczinski as new CEO, reports the news agency AP. Kempczinski comes from the post of Chairman of McDonald's USA and thanks in a statement Easterbrook, which he calls his mentor.
Started in the company in 1993Steve Easterbrook started working for McDonald's in London in 1993 and became the chief executive of the multinational fast food giant in 2015.
He is considered to be behind several changes in recent years, including the vending machines where customers order their meals. Market capitalization has more than doubled since becoming CEO, BBC writes.
McDonald's is not the only company to ban relationships of this kind. The CEO of Intel software giant Brian Krzanich resigned last year after five years due to a relationship with an employee of the company.