Emanuel's office said that officers in the Grand Central, Grand Crossing and Chicago Lawn districts will get the cameras as the "next step [on] the road to reform."
Every officer patrolling the streets of Chicago will wear a body camera by the end of the year, a full year ahead of schedule, officials said.
"Body cameras offer a firsthand look into the dangers face officers every day and will allow us to see what we're doing right and where we can improve our training and tactics," Chicago Police Supt. Eddie Johnson said. "We will continue to make investments that make our officers safer and build community trust."
Expediting the camera rollout cost the city $2.8 million, in addition to the $8 million initially earmarked for the program in 2017, according to the Mayor's Office.
The extra money came from funds left unclaimed in the city's property tax rebate.
The cameras are designed to "to strengthen investigations, improve transparency and build trust within the communities that police serve," according to the Mayor's Office.
The cameras can record eight hours of footage on a single charge, which can be wirelessly uploaded to Chicago Police Department servers, officials said.
A federal investigation of the Police Department sparked by the fatal shooting of Laquan McDonald and completed in January endorsed the expedited schedule to equip all officers with body cameras capable of recording their interactions with members of the public.
When officers are in public or in a private residence or business while on duty, they are expected activate their cameras and will be held accountable for recording their encounters with citizens from the start, officials said.
The Justice Department report said the cameras would have no impact on the operations of the Police Department unless officials collaborate "with police unions and community groups on policies and protocols for body camera usage and develop better accountability measures."
The current policy is insufficient, the federal investigation found.
"There is no policy directing supervisors as to when or whether they regularly review recordings to ensure proper use of the cameras and identify officer training opportunities or conduct concerns," according to the report. "Further, current policy does not explicitly provide that an officer who deliberately fails to use his or her assigned body-cam properly will face discipline."