Liam Robinson was able to call up emergency services after he remembered some advice from the children's show's lead character, reports The Mirror.
A line from a song on the long-running show tells children how to "dial 999".
Liam's mother Rebecca Forsyth - who is currently pregnant - collapsed at her home with her young child nearby. When she awoke, he was waiting at the front door for an ambulance.
She explained: "He climbed on the bookshelf to reach the phone and rang the ambulance. We had taught him to ring 999 in an emergency."
However, she added that he knew how to ring the number due to the song in Fireman Sam.
"He was amazing, we are just so proud of him," she added.
Liam Robinson will be given an award from the North East Ambulance Service for his bravery and calm actions.
Watch the intro for the classic version of Fireman Sam below: