Erfan Ali was just six years old when he was attacked by his neighbour's Rhodesian Ridgeback called Tyson.
It jumped through a broken wooden fence before attacking the boy in his family's garden, in 2011.
The dog's owner Kevin Large was jailed in 2012 after he admitted failing to control the animal.
Now Erfan's family has won a payout after launching civil action against Large's mother - for not properly maintaining the garden fence between the neighbours in Gabalfa.
Michele Skinner, 52, was ordered to pay the compensation by a judge at the Cardiff Civil Justice Centre.
The boy's legal team claimed damages because Erfan, now 11, will have facial scars for the rest of his life and because of the psychological trauma he suffered.
Erfan's dad Dilwar Ali , 49, said: "This action was never about the money but the principle.
"People need to be able to feel safe in their neighbourhoods without fear of attack from dogs.
"Now hopefully this award will act as a deterrent to unruly dog owners and afford some protection to residents in similar situations."
The family's lawyer said it could lead to many more compensation cases.
Erfan needed emergency surgery at the specialist Welsh Centre for Burns and Plastic Surgery at Morriston Hospital in Swansea.
Since then he has had multiple skin grafts and will need further operations well into his teenage years.
A Cardiff boy who was scarred for life after being savaged by his neighbour's dog has been awarded £70,000 compensation.