The fire started around 5:19 a.m. Tuesday at the Jefferson Square Condominiums on the 1200 block of Cooper Street in Edgewater Park.
Officials say the bulk of the blaze has been extinguished.
The injured person was taken to the hospital in unknown condition.
Chopper 6 was over the scene as crews worked to douse the flames.
Chopper 6 over fire at Edgewater Park, NJ condo