Body cam footage shows Charles Hicks II crying for help as John Turnure forces snow into his mouth while restraining him in Akron, Ohio.
Hicks, who is black, shouts “I can’t breathe sir, I can’t breathe”, echoing the words of George Floyd who died after police officer Derek Chauvin placed his knee on his neck in Minneapolis.
Akron Police Chief Mike Caprez announced on Thursday that Turnure, who is white, had resigned on 30 March.
He said it was for “various personal and professional reasons”, and it was not an admission of wrongdoing.
With an internal investigation still ongoing, Mr Caprez said: “Up until the time snow was used, it was textbook… we did everything right up to that point.”
Akron’s mayor Daniel Horrigan said: “We disrespected a citizen and for that I apologise.”