Moose, five, was left critically injured and suffered five broken bones in his leg after he was struck by two different cars outside his home in Dudley.
A fundraising campaign raised more than £1,000 for his operation but the retired racing dog died after he went into cardiac arrest during surgery.
It was a bitter pill to swallow for his owner Lindsay Winters, 43, who was taken aback by people's generosity who donated money on Moose's GoFundMe page.
She said: "I just want to thank people and raise awareness of GoFundMe. We raised £1,000 in the first day. We had so many lovely messages off people and we didn't even know them.
"People are on furlough and short of money these days but they still donated. It has really opened my eyes to crowdfunding."
Lindsay described Moose as a "lovely, affectionate and handsome" dog.
Tragedy struck after a neighbour came round to see Moose in Lindsay's back garden on Saturday, May 29.
Lindsay went to take the racing hound a walk but Moose got "all excited" and ran out through the back gate "which hadn't been shut properly", she said.
She heard a loud thud followed by a yelp.
"My boy was hit by one car, spin round and was hit by another car coming from the other direction," she said. "He was lying in the road bleeding but was awake."
The first car drove away but the second car stopped.
Moose was scooped off the road by Lindsay's partner before the couple rushed him to a veterinary surgery.
The vets said Moose needed surgery - but the cost of the operation exceeded his insurance cover of £4,000.
The couple decided to launch a fundraising page on gofundme.com and raised an additional £1,404 to meet the costs.
However, Moose died after going into cardiac arrest "on the table" last Tuesday, June 2, she said.
His fundraising page has now been disabled. Lindsay also paid tribute to her partner who "stayed calm" and comforted Moose when he was run over.
"Moose is a big dog and my partner was able to lift him out of the road," she said. "He was the hero of the hour."