The random attack happened shortly after 7 p.m. on the NJ Transit concourse inside Penn Station.
Police say the suspect is a homeless, emotionally disturbed person known to frequent Penn Station. Authorities said the suspect was taken into custody by responding officers. Video from the scene showed police placing the suspect in a wheelchair as he was escorted away.
Investigators recovered a knife on the NJ Transit side of Penn Station that is believed to have been used in the attack.
Amtrak police were among the first agencies to respond after the emergency call came in around 7 p.m. Sunday. Medics rushed all five victims to Bellevue Hospital.
Officials said one person suffered serious injuries, two people suffered moderate injuries and two others sustained minor injuries. All five victims are expected to survive.
The incident left commuters shaken and raised concerns among workers inside one of the city's busiest transit hubs.
"I'm working here. And so not only me, my coworkers too, my supervisor. So when something like this happens, we're terrified. It's about our own safety as well," one Penn Station employee said.
Authorities have not released the suspect's identity or announced potential charges.
Mayor Zohran Mamdani took to social media to thank first responders for their swift response and said his administration remains in contact with law enforcement as the investigation continues.