Haus, a 2-year-old German shepherd, was picked out from the animal shelter by the DeLuca family two months ago.
He has already repaid the favour, risking his own life to protect their 7-year-old daughter, suffering three bites as he fought off a deadly rattlesnake in Florida.
His story has spread across America and wellwishers have donated more than US$50,000 to help pay veterinary bills for Haus who is being treated with anti-venom and painkillers. He is expected to recover from his encounter with the Eastern diamondback.
Molly DeLuca's grandmother was watching her play with the dog in their back garden in Tampa when she spotted the dog leaping in front of the girl.
It was only later, when they took him to the vet for his bleeding leg, they discovered what had happened. When his leg was shaved it revealed tell-tale fang marks from one of the snakes that lives in a nearby state park.
Molly's father Adam DeLuca told AP: "He just exceeded our expectations all the way around. Right away, the kids were hugging and loving on him, he always took it, he never did anything.
"Whenever anyone came to the door, he would start barking and try to be protective.
"He has just been an amazing dog. He's the type of dog that when you want to go buy a dog, you pay thousands of dollars and that's the dog you get. But we adopted him and got him for free."
A family friend set up a GoFundMe account to pay for the treatment and donations raced past the US$15,000 target.
Now they are asking for cash to go instead to a local animal shelter.
"Haus has enough money to meet his needs," they said in a message posted on the site. "Many other beautiful German Shepherds like Haus are waiting on you."