Witnesses say flames were pouring from the home in the 3000 block of N.C. Highway 96, just north of Selma, when firefighters arrived.
The injured firefighter was on the roof battling the flames when conditions became dangerous.
He fell as he was coming down the ladder.
Rescue crews rushed him to WakeMed with a serious leg injury.
Johnston County fire investigators are working to find a cause for the blaze.