Smurf the miniature Shetland was found next to a dual carriageway in Washington 26-years-ago and was rescued by Lisa Walker and her dad.
They planned to shelter him for the night at the farm where they worked, but Smurf stole Lisa's heart and she was allowed to keep him as her 18th birthday gift.
His work as a therapy animal with older people – as well as children with special needs – began after he visited the home where Lisa's husband worked.
Christmas light switch ons, fundraisers and panto appearances at the Whitley Bay Playhouse added to his fame.
Six years ago he lost his own sight, but his disability did not stop him forming strong bonds with the elderly.
Lisa, 45, who lives in Cambois, said Smurf first became well-known when she took him on the walk to collect her children from school, going on to become the face of Mini Pony Hire, which she runs with son Alex, 21.
Lisa said: “I ensured Smurf was licensed and he struck up amazing bonds with the elderly.
"He would make a lot of them reminiscence about their days in the mines with the pit ponies.
"He became such a big part of the children's lives.
"They could see he was disabled after losing his sight and it would inspire them.
"When he lost his sight I decided to retire him but he would just try and get into the van because he wanted to come everywhere still.
"So we had to train him to climb in since he had no sight."
Smurf made history last year when he became the first pony to be named as the Horse & Hound horse of the year.
He became poorly at the weekend, and after being kept in the vets for the night, Lisa got the call say he had gone down hill.
She said: "People have contacted me from all over the world paying tribute.
"On a personal level it's the fact he has been a constant in my life, I joke he was the first to know everything."