"The option to use active duty forces in a law enforcement role should only be used as a matter of last resort, and only in the most urgent and dire of situations. We are not in one of those situations now. I do not support invoking the Insurrection Act," he said during a briefing at the Pentagon.
Esper also attempted to explain his use of the word "battlespace" when discussing quelling violence on the streets amid civil unrest.
"It's something we use day in and day out ... it's part of our military lexicon that I grew up with...it's not a phrase focused on people," he said. "In retrospect I would have used different wording."
Esper also addressed the killing of Floyd, calling it a "horrible crime" and said "racism is real in America, and we must all do our very best to recognize it, to confront it, and to eradicate it."
"The killing of George Floyd by a Minneapolis policeman is a horrible crime. The officers on the scene that day should be held accountable for his murder. It is a tragedy that we have seen repeat itself too many times. With great sympathy, I want to extend the deepest of condolences to the family and friends of George Floyd from me and the Department. Racism is real in America, and we must all do our very best to recognize it, to confront it, and to eradicate it," he said.
As tear gas wafted through the air in Lafayette Park across from the White House, Trump announced from the Rose Garden that if state or city leaders refuse "to take the actions that are necessary to defend the life and property of their residents," he will invoke the Insurrection Act, an 1807 law that allows a president to deploy the US military to suppress civil disorder.
Esper and Gen. Mark Milley, chairman of the Joint Chiefs of Staff, have faced a flurry of questions in the wake of Trump's comments, pressure that culminated in Esper's appearance at the Pentagon briefing room podium Wednesday.
Milley did not appear with Esper at the Pentagon press briefing Wednesday.
When asked why he was not present, a defense official told CNN it is because Milley believes it is up to the political and civilian control to explain the current situation.
Milley was at the White House on Monday in his battle fatigues and walked over to St. John's church with President Trump's entourage but did not participate in the actual photo-op that occurred.
Later Monday night, Milley travelled the streets checking on protests and the security response. The Military Times caught up with Milley who talked about the right of people "to protest, but protest peacefully."