Minnesota police said 46-year-old Mr Floyd, who had worked providing security at a restaurant, died after a “medical incident” in a “police interaction”.
On Tuesday afternoon, Mayor Jacob Frey confirmed the four officers involved in the incident had been “terminated”.
Minneapolis Police Chief Medaria Arradondo said the four officers were now “former employees”.
Footage shows the man, George Floyd, groaning and repeatedly saying “I can’t breathe” to the white officer.
The incident echoed that of Eric Garner, a black man who died being arrested in New York City in 2014.
The FBI has said it will investigate the Minneapolis incident, which took place on Monday evening.