Nixon signed the orders Saturday in response to days of rioting and nighttime looting and vandalization of businesses near where the shooting took place Aug. 9.
He said the orders were in response to the "very few" who had acted violently Friday night with the "intent of committing crimes and endangering citizens. That is unacceptable."
Nixon applauded "the courage and resolve of peaceful protesters who stood up against violent instigators."
"This is a test. The eyes of the world are watching" - Missouri Gov. Jay Nixon.— Joel D. Anderson (@blackink12) August 16, 2014
During Nixon's press conference Saturday, activists shouted out and expressed anger over the shooting.
"You need to charge that policeman with murder" is the first, uh, question directed at Gov. Nixon. #Ferguson— Joel D. Anderson (@blackink12) August 16, 2014
The curfew is scheduled to run from midnight to 5 a.n.