Rita Kimball, Spike's owner, said she and her family found the canine in the parking lot of a Camden grocery store 13 years ago.
"He had been shaved up his back, had blood stains around his neck from a chain or rope, and looked pretty rough," Kimball told Guinness World Records. "The clerk in the grocery told us he had been there for three days and they were feeding him scraps."
Kimball decided to bring the dog home to her small farm, where he immediately fit in. She dubbed him Spike.
"Spike was a name for a large dog. My guy was small, but he had the attitude of a big dog," she said.
Kimball took Spike to a veterinarian, who determined the canine's likely birthday as Nov. 10, 1999.
Kimball said she was watching The Tonight Show with Jimmy Fallon one night when she learned about the former oldest dog living, Pebbles, and realized Spike was older.
"Most of our family knew that Spike was old, but didn't know he had a shot at being the oldest in the world," Kimball said. "Now that he is a record holder, they see him as a celebrity."