Derek Chauvin, who is white, was shown in footage kneeling on 46-year-old George Floyd's neck on Monday. He and three other officers have been sacked.
Days of looting and arson in the Minnesota city have boiled over into nationwide protests.
The case has reignited US anger over police killings of black Americans.
Hennepin County Prosecutor Mike Freeman said Mr Chauvin was charged with third-degree murder.
He said he "anticipates charges" for the three other officers but would not offer more details.