Firefighters said the oldest probably saved his younger sibling’s life by pushing him under a bed when the quake struck.
Cheers greeted the rescue of the youngest, seven-month-old Pasquale Marmolo, who was extracted from the ruins of his parents’ house at around 4am on Tuesday.
Video showed him wearing a white sleepsuit and appearing alert as he was passed to safety surrounded by dozens of emergency personnel.
The 4.0-magnitude quake on Monday evening left two people dead and caused panic on the island at the north end of the Bay of Naples.
The second brother trapped in the wrecked house in Casamicciola, seven-year-old Mattia, was pulled out seven hours after his baby brother.
He was covered with cement dust and quickly loaded onto a stretcher and into an ambulance.
Another two hours later, 11-year-old Ciro emerged and was also whisked to hospital where his parents were waiting for him.
He was greeted by his pregnant mother, sitting in a wheelchair after she escaped through a bathroom window.
The boys’ father, Alessandro, was also waiting, his hands bandaged following a fracture he received when the entire second floor of the house collapsed.
“It was a terrible night. I don’t have words to explain it,” he told RAI state television.
He said the older boys had been in the bedroom while the baby was in a playpen in the kitchen.
Hospital officials said the three brothers were doing well, after the older two boys were treated for dehydration and the oldest for a fracture to his right foot.
They were expected to be discharged on Wednesday.
The quake struck at around 9pm local time, killing an elderly woman who was inside a church when the tremor caused it to collapse.
Dozens of others were injured and taken to hospital.
At least 14 aftershocks were felt.
Helicopters and a ferry brought in more rescuers from the mainland, and three extra ferries were provided during the night for about 1,000 residents and tourists who wanted to leave or end their holidays early.
The earthquake came two days before the first anniversary of the devastating 6.2-magnitude tremor that killed almost 300 people, including three Britons, in Amatrice, central Italy.
Italy is one of the most seismically active in Europe, sitting at the meeting point of two tectonic plates, which continue to move at a rate of around 3cm a year.
© 2017, Vale of Glamorgan Broadcasting CIC T/A: Bro Radio & Sky News.