Teddy, a mixed-breed, toy-loving puppy that sports a brown and white coat and a wide grin, arrived at the Animal Shelter of Martha’s Vineyard in the spring. Dogs rarely stay long at the shelter as they are in high demand on the Island, said shelter manager Lisa Dawley.

But month after month, Teddy remained, frightening any potential adopters with a fierce charge and menacing growls. He was distrusting of strangers, and Ms. Dawley feared Teddy would never find his rightful home.

Then Jeremy Jones arrived.

Saba learns to stay. — Ray Ewing

A dog trainer for 20 years, Mr. Jones worked diligently with Teddy to transform him from aggressive and reactive, to warm, companionable and adoptable. And after nearly 100 hours of training and five months at the shelter, Teddy landed his new Vineyard home.

“The first time I met him, I was pretty sure he was going to bite me,” said Mr. Jones. “It took, I think, three whole visits before I could actually get him to take treats from me.... But then as he got more comfortable we started to make a lot of progress and I would walk him around town. He needed — and still needs — a lot of work, but he’s a sweetheart of a dog.”

Mr. Jones said that Teddy required the most training out of his vast portfolio of canine clients, but his years of experience and apprenticeship under acclaimed Vineyard dog trainer and author, Tom Shelby, readied him for the challenge.

“I’ve personally seen [Mr. Jones] conduct some amazing transformations,” said Ms. Dawley. “He’s brought dogs from zero to 100.”

Mr. Jones has been working with Ms. Dawley and the animal shelter for several years. He offers complimentary training sessions to people with newly-adopted dogs and leads group puppy classes in the fall and spring.

But Mr. Jones’ connection with dogs did not come naturally. The Oak Bluffs native has been a dog owner since childhood, but his family took a rather hands-off approach to pup-raising, he said.

Jack gets a treat. — Ray Ewing

“We had a big lab when I was a kid, and back then, the dog would just roam freely around town,” said Mr. Jones. “Then the dog would show up around dinner time to get fed.... So overall I just didn’t really have any interest in dogs for a long time.”

This changed two decades later when Mr. Jones, then 30, moved into a home in Washington D.C. with nine roommates and an unexpected litter of pit bull puppies. He took to one pup, Billie Holiday, in particular, and knew that it was time for him to find some canine companionship.

“[The puppies] were all named after jazz musicians,” said Mr. Jones. “Most of them found other homes, but I had this insane roommate named Couch who ended up keeping Billie Holiday. And, yeah, I just really fell in love with that dog. But Couch was very possessive.”

So Mr. Jones adopted a greyhound-pit bull mix off of petfinder.com, and it was then that his training career began.

The dog was fearful, anti-social and aggressive. But after reading through Dogs for Dummies and other training books, Mr. Jones turned his new family member into a gentle and confident dog.

Bear gets som leash work. — Ray Ewing

More dogs followed, and when Mr. Jones realized his knack for training, he reached out to Mr. Shelby — an Islander with a longtime reputation for his mastery of dog training — and asked to learn his ways.

For six years, Mr. Jones accompanied Mr. Shelby to training sessions around the Vineyard, studying his techniques and the behaviors of various dog breeds. In exchange for the lessons, Mr. Jones, who is also a professional carpenter, spruced up Mr. Shelby’s cottage in the Oak Bluffs Camp Ground.

“I got the better deal by far,” said Mr. Jones.

Mr. Jones has since trained hundreds of dogs on the Island and has left behind his carpentry service to work full time as a private and group trainer. A spot in his puppy classes are in high demand.

“About three years ago, Lisa said to me that she really wanted to turn [the shelter] into a community place with more activities,” said Mr. Jones. “So I started leading puppy classes... and now they’re really popular.”

Mr. Jones began working with dogs 20 years ago. — Ray Ewing

The key to training dogs of any age in any setting, he added, is to train their owners, too.

“Teaching the owners to deal with their dog is just as — or more — important,” said Mr. Jones. “And in most cases, the dogs learn faster.”

Not every client is ultimately a success story, but the craft is undeniably rewarding, said Mr. Jones.

“It’s the best job I’ve ever had, and I’ve had a lot of jobs,” he said. “One of the best parts isn’t even the dogs, it’s meeting all of the people... and helping them to understand their dog’s behavior and personality better, and just make their lives better.”

After a long day on the job, his work is far from over when he returns to his home in Oak Bluffs. Mr. Jones and his wife have two horses, two donkeys, two dogs, two tortoises, one cat and a fish pond that need tending to.

The most demanding of the bunch is its newest member, Esme, an 18-month-old Australian cattle dog whose specialty is barking and getting up to mischief.

“She’s an incredible pain...,” said Mr. Jones. “But without her, my life wouldn’t be as interesting.... I think I’m going to teach her how to ride a swing.”

For more information about puppy classes at the Animal Shelter of Martha’s Vineyard, visit animalshelterofmv.org or call 508-627-8662.