Authorities said the driver weaved through Rittenhouse Square, a popular destination, at about 3:30 p.m. before crashing at 18th and Walnut streets.
"I ran up and grabbed the wheel and he was still trying to fight," witness Brandon Thompson recalled.
Thompson said he was one of the handful of Good Samaritans who helped end the man's dangerous joyride.
"The only thing on my mind was that he needed to be stopped," Thompson said.
Alyssa Wolfington said she saw the man yelling around the corner just minutes before the incident happened.
"The man was originally standing in front his apartment building yelling," Wolfington said.
Police said the man carjacked taxi driver Michael Emmanuel who was dropping off a customer.
"When she paid me, he came to the passenger side door and grabbed the lady from her hair, from her collar, and dragged her on the street," Emmanuel said.
Rushing to help his customer, Emmanuel said he left his taxi unattended.
"He took off his clothes, opened the door, ran in the car, and drove off," Emmanuel recalled.
Witnesses captured the driver hitting parked cars and weaving through the park.
Pedestrians like Kyra Howell had to run for cover.
"I honestly saw my life flash before my eyes," Howell explained.
Sources told ABC7 sister station WPVI that the man may suffer from mental health illness. No injuries were reported.
"It's crazy, it was crazy. Thank God it wasn't 5:30 and people were picking their kids up from school," witness Emily Goodman said.
The man was taken to the hospital and officials said he could face several charges including assault and car theft.