It happened around 4:30 p.m. at CJ Beauty Supply inside a strip mall near the intersection of Chicago and Kedzie. The car went completely inside the store.
The accident was caused by Tameka Turner, a passenger who had been sitting in the car while it was parked nearby. A 2-year-old baby was in the back seat at the time.
"I tried to reach over to turn the car off because the baby was crying and it was going forward and I tried to hit the brakes, but I must have hit gas and it took off," said Turner, who does not have a driver's license.
The baby's mother, Jentille Young, was inside the store when she saw the car come shooting through the window.
"I didn't even know it was my car until I looked and saw the license plates," said Young.
In her concern for the baby, Young says she didn't notice the car hit one of the store's employees, Mijeong Jang, 50. Turner says she never saw her.
"I didn't see nobody. Like I said, it happened so fast," said Turner.
Jang was released from the hospital Thursday evening. Her relatives say she is expected to be OK.
Witnesses say the crash was terrifying to watch.
"All of a sudden, you could tell she hit the gas, not the brake," said witness Keith Hall. "The car went flying into the window."
A tow truck driver carefully pulled the car out of the building, making sure to avoid the building's support beams. Cleanup crews had a long job ahead to put the store back together.
"I feel terrible, scared, I never drove a car before in my life, and I hope that lady's all right," said Turner.
Police are still investigating. They have not determined whether they will issue any citation or file any charges in the case.