A Manhattan judge agreed Tuesday to close Willis' case without jail time or probation if she does two days of service.
The Brown University student didn't have to be in court or enter any plea.
Her lawyer, Stacey Richman, says prosecutors "took a logical approach to assessing the situation."
Willis was arrested last month. Police said she was sipping a beer in Union Square in violation of an open-container law.
Police said she also gave them phony identification - a misdemeanor. She was 20 then and turned 21 this month. Scout is the second of Moore and Willis' three daughters together. They divorced in 2000.