It happened at a multi-family home on Jay Avenue just after 5:30 a.m.
The call initially came in as an argument on the street, but when police and firefighters arrived, they discovered the house on fire and one resident had jumped out of a second-floor window.
Firefighters pulled another victim from the second floor who was found unconscious and in need of medical attention.
Two other residents were rescued from the roof.
"The police department employee had a tactical ladder on the lower roof, the fire department deployed their aerial ladder to remove the second victim, the third victim self-extricated, he jumped from the window, and then the fourth was located with our para-search team," said Lyndhurst Fire Chief Paul Haggerty.
The victim who needed CPR is said to be critical but stable.
The fire was brought under control and the cause is under investigation, but officials say it does not appear to be suspicious.
The Red Cross is helping the victims from two families.
The fire chief said they never heard any working smoke detectors inside the home.
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