Jack Jones, of Lightmoor Village, in Telford, received a special commendation from West Midlands Ambulance Service after he took lightning fast action earlier this year.
"I was doing Jack's sister Poppy's hair after breakfast and her head dropped to one side," said grandma Marilyn Jones, 71.
"I thought she was just being playful but Jack recognised she was having an epileptic fit."
Fast-thinking Jack leapt into action, rushing round to stop Poppy, aged six, from falling onto the floor head first.
It's not the first time that Poppy has had a fit and thoughtful Jack knew how to put her in the recovery position on the sofa while 999 was being called.
"We live in a secluded area, so Jack and his brother Sam went out to make sure that the ambulance people know which way to come," said Marilyn.
And when an ambulance crew and a paramedic arrived, they were ushered to see where Poppy was.
"Jack was able to answer all their questions and Poppy was taken off to hospital for checks for a couple of hours," said Marilyn.
"It was all incredibly upsetting for the family but Jack came and gave me a hug. And when his other grandma rang up he told her that Poppy had gone off in the ambulance smiling."
Jack and Poppy dote on each other and after his actions in June this year he received a commendation certificate from the ambulance service last week.
Now the staunch Liverpool fan is the talk of his own football club, Wrekin Juniors, where he plays in goal, as well as Lawley Primary which he and Poppy attend.
His family too - mum Louise and dad Russell - especially are is glowing with pride.
Marilyn said: "The certificate for a young person of outstanding bravery praised Jack for his actions in saving his sister's life and it was that serious. But hopefully Poppy won't have any more fits, but they don't know the cause."