The crash happened just after 6:30 p.m. inside Commodore Barry Park at Flushing Avenue and Navy Street in the Fort Greene section of Brooklyn.
Police say a 53-year-old woman, identified as Neisha Atkinson, allegedly lost control of the three-wheeled motorcycle and struck a group of people in the park.
Authorities say seven men and five women, ranging in age from 36 to 73 years old, were hurt. All 12 victims suffered non-life-threatening injuries and were listed in stable condition Monday morning.
Witnesses told Eyewitness News the park was crowded for a special event featuring a DJ when the motorcycle drove into the gathering.
Video from the scene showed what appeared to be a chair lodged in one of the motorcycle's front wheels following the crash.
Police have charged Atkinson with two counts of reckless endangerment, reckless driving, failure to yield to pedestrians and improper licensing. She was also injured in the crash and is recovering at a hospital.
People who know the driver told Eyewitness News they do not believe the crash was intentional.
"She's not a bad person, she's a good person. I'm telling you that she's a good person," said Mike Smith.
"And then she turned and she hit everybody over here. Everybody that was sitting here went up in the air," witness Kim Tammy said.
The investigation into the cause of the crash remains ongoing.