The fire erupted around 11:30 p.m. Monday at the home of Archie and Donna Monroe in the 100 block of West 37th Street.
Firefighters arrived to find flames erupting through the front door.
They were told someone was trapped inside, but they first had to bring the flames under control.
When they were able to enter the home, rescuers found Archie inside.
Deadly Wilmington Fire
His stepdaughter, Jorgina Dennis-Watson, said he went inside the burning home in an effort to save his wife of more than 30 years.
She was at the scene of the fire.
"I didn't know where my mom was. I'm going up the street yelling 'Where's my mom?' And the neighbor across the street said 'She's here, she's here," said Dennis-Watson.
Officials say her mother survived by jumping out a second floor window, though she was critically injured. A neighbor who tried to catch her sustained a non-life threatening injury.
Man killed trying to rescue wife from Wilmington fire
Dennis-Watson said it was a relief to hear that her mom made it out, but then tried to figure out what happened to her stepfather.
"Someone said 'he ran back in to get your mom, he ran back in to get your mom,'" she said.
He was taken to the hospital in critical condition, but was later pronounced dead.
"That shows the character of a person. When a person is out of the fire, but he goes back in and tries to retrieve his wife. That alone shows his character," said longtime friend Darrell Armstrong.
Everyone is this quiet neighborhood knew Archie Monroe. Family members were in shock, and so were longtime neighbors.
"Archie was just that all-around neighbor that you could call on if you needed help. He was the guy who used to watch everybody's cars. He had a little car detailing hobby," said neighbor Angie McCloskey.
The fire marshal said it could take until sometime next week to determine the cause of the fire.