Ibrahimovic enjoyed plenty of success in his maiden campaign at Old Trafford last time out, ending 2016-17 as the club's leading goalscorer in all competitions.
The 36-year-old damaged his cruciate ligaments in a Europa League match last April, however, which kept him out of action for the vast majority of 2017.
A separate injury has curtailed his appearances this term, too, with just six outings under his belt - only one of those being a Premier League start.
Following months of speculation that he could be on his way to the United States, where he will now likely see out the remaining years of his playing career, United have confirmed that Ibrahimovic's time in English football is officially over.
A club statement read: "Everyone at the club would like to thank Zlatan for his contribution to the team since his arrival and wishes him well for the future."
Ibrahimovic, who still had three months left to run on the deal signed last year, bows out of Old Trafford with a record of 29 goals in 53 appearances.