The neighborhood, which has a reputation for poverty and crime, appeared calm at midday on Sunday after businesses were burned, cars set ablaze and gunshots fired by demonstrators angered by the police killing.
Police presence in the Sherman Park neighborhood was low with some residents milling around and others cleaning up debris.
Police violence against black men and women has sparked intermittent, sometimes violent protests in U.S. cities from Ferguson, Missouri, to Baltimore and New York over the last two years.
The outrage has given rise to the Black Lives Matter movement and touched off a national debate over race and policing in the United States.
Sheriff David Clarke, nationally known as a conservative voice in Republican politics, asked that the National Guard be mobilized to help contain the protests, said Fran McLaughlin, a spokeswoman for the sheriff’s office.
She said he made his request publicly after meeting with Republican Governor Scott Walker and Major General Donald Dunbar of the Wisconsin National Guard, the two men who would consider deploying the Guard.
The sheriff’s office typically oversees county-level law enforcement matters such as county courts, jails, and pretrial services but deployed officers and equipment to help quell Saturday night's riots
The trouble started on Saturday afternoon. A patrol officer fatally shot a suspect who fled after police stopped his vehicle, police said.