The blaze broke out around 4:30 a.m. Wednesday in a house on the 1100 block of North 24th Street.
The fire quickly grew into towering flames that poured through the dwelling's windows, doors and roof.
Police say the injured man went back into the burning house to make sure everyone else in his famiily had made it out.
Investigators say it turns out that everyone had already escaped the flames without any injuries.
The 59-year-old man is in serious condition at Cooper University Hospital.
The Red Cross reports that ten adults and one child were displaced by the fire. They say the house was subdivided into four units.
The search for a cause will begin once the embers cool.