Officer Darren Wilson is no longer a member of the Ferguson Police Department.
Wilson's resignation Saturday comes less than a week after a grand jury declined to indict him in the fatal shooting of Michael Brown.
Attorney Neil Bruntrager says his client's resignation is effective immediately. Wilson had been on administrative leave since Aug. 9.
In a resignation letter sent to Ferguson officials on Saturday night, Wilson said he hoped his stepping down would “allow the community to heal.” But activists called it too little, too late.
Ferguson Township committeewoman Patricia Bynes says there are so many others who are more responsible than Wilson for the tension in Ferguson.
“The governor. Chief Belmar. Chief Jackson. Bob McCulloch. There is so many other people involved who need to be held accountable for the things that have gotten us to this point right now.” -- Patricia Bynes, Ferguson Township committeewoman
Ferguson mayor James Knowles was not available for comment. A spokeswoman for the city said Chief Tom Jackson would not be making any statement.
Wilson will retain his peace officer license in Missouri, but former Ferguson mayor Brian Fletcher says he doubts Wilson will ever be a police officer again.
"He didn't have to resign. He could have come back immediately if he wished to. I'm sure he had a conversation with his family, he's had a chance to think about this. “For everybody's sake, both the community and Darren Wilson's sake and the Brown family, I think he's made the right decision." -- Former Ferguson Mayor Brian Fletcher
A spokeswoman for the city of Ferguson said Saturday night that city officials haven't yet received word of the resignation, although Bruntrager disputes that.
A grand jury spent more than three months reviewing evidence in the shooting incident before deciding that the 28-year-old police officer would not be charged in the case. The confrontation and grand jury decision sparked continuing protests in the St. Louis suburb and across the country.
The St. Louis Post-Dispatch posted the full text of Wilson's resignation letter:
"I, Darren Wilson, hereby resign my commission as a police officer with the City of Ferguson effective immediately. I have been told that my continued employment may put the residents and police officers of the City of Ferguson at risk, which is a circumstance that I cannot allow. "For obvious reasons, I wanted to wait until the grand jury made their decision before I officially made my decision to resign. It was my hope to continue in police work, but the safety of other police officers and the community are of paramount importance to me. "It is my hope that my resignation will allow the community to heal. I would like to thank all of my supporters and fellow officers throughout this process."
Rachel Lippman of Illinois Public Radio and NPR News contributed to this report