Global Chief People Office David Fairhurst has left the company, a company spokesperson confirmed to FOX Business.
An internal memo sent out Monday by Easterbrook's successor, Chris Kempczinski, did not provide a reason for the departure, according to Bloomberg.
Fairhurst had worked for McDonald’s for just shy of 15 years and was promoted to the highest human resources position by Easterbrook in 2015. Senior Vice President Mason Smoot will take over on an interim basis, Bloomberg reports.
Easterbrook’s exit from the company was announced late Sunday, after the restaurant chain’s board of directors voted in favor of the departure on Friday.
The fast-food giant said Easterbrook demonstrated poor judgment, and that McDonald's forbids managers from having romantic relationships with direct or indirect subordinates.
Easterbrook confirmed the relationship in an email to employees, saying: “Given the values of the company, I agree with the board that it is time for me to move on.”
The identity of the co-worker in question has not been revealed.
Also on Monday, McDonald's revealed Easterbrook is eligible for a half year of severance paid at the end of the six-month period.
Former McDonald’s USA CEO Ed Rensi said Monday that the burger giant made the right decision by firing Easterbrook, calling the situation "inappropriate."
"In this day and age it is just unthinkable that anybody would do that," Rensi told "Cavuto: Coast to Coast." "The mistake was made, it's been corrected."
Rensi added that the relationship, which McDonald's said violated company policy, and subsequent fallout negatively affected more than just Easterbrook.
"The stockholders got hurt today, the employees got hurt, the reputation got hurt," Rensi said. "Easterbrook's going to walk away with a lot of money, but he was terminated. Nothing good's going to come out of this except it oughta wake people up and do what's right."
FOX Business' Grady Trimble and the Associated Press contributed to this report.