If you want to understand Don Chiofaro, it helps to stand deep in his backyard, behind the house on Belmont Hill where he has lived for 35 years. He has 6 acres of thick woods back here, next to a wildlife habitat. It’s quiet, the only sounds from birds and the occasional squirrel skittering down a 70-foot maple tree, and easy to forget you’re 20 minutes from downtown Boston.

And it is here that Chiofaro, the onetime Harvard football captain who built the biggest skyscraper in the city in the 1980s and has battled for a decade to build another on the Boston waterfront, envisions a decidedly more modest undertaking: five houses on a cul-de-sac.

It’s an unusual project for a downtown developer, who, at age 70, has never built something as straightforward as a house. And this being Chiofaro, there is nothing straightforward about his latest venture, which has him at odds with neighbors in the town where he has lived nearly all his life, a sparring match with echoes of Chiofaro’s famous battles in downtown Boston.

But the eternally optimistic builder is looking forward to a new challenge: turning his backyard into a small subdivision.

“I’m excited about building these houses,’’ Chiofaro said. “I want to learn how to do it.’’

Ask the obvious question — why are you doing this? — and he says it’s for his kids and his business, so The Chiofaro Co. can learn all sides of the development game and last long after he’s gone. And it’s also for Belmont, he says, to boost the tax base and enable five more families to live in the great town where he grew up as the son of a police officer and became neighbor to a governor.

Ask again why he has spent three years and $150,000 trying to wrangle permits for five houses when, at his age, he could be sipping mai tais on a beach somewhere, and Chiofaro’s answer takes six hours to unspool.

It begins at his office on the 46th floor of International Place, the circular tower he built in downtown Boston three decades ago, a monument to Chiofaro’s will. The answer continues in the car, over a long drive to Westborough and Westford, where he shows off the vast office parks he carved out of farmland in the 1980s, and it concludes in Watertown and West Cambridge, where he’s eyeing parking lots and industrial corners for projects he’s not quite ready to unveil.

And over that long ramble, a simple explanation emerges: Whether in Belmont or Boston, Chiofaro does it because he loves the game. And he’s not about to stop.

“These projects are like puzzles,’’ he said. “You look at a place and see something no one else can see. Then you have to solve all these problems to get it done.’’

The puzzle-building began 40 years ago, when Chiofaro bought 70 acres for that office park in Westborough. A decade later he pieced together 10 parcels in downtown Boston to pull off International Place, at a time when the edge of the Financial District felt like an urban frontier.

International Place, which The Chiofaro Co. still runs today, was the kind of undertaking that rewarded vision and stubbornness, qualities Chiofaro has in spades, said Michael McCormack. He was on the Boston City Council when Chiofaro proposed the building, and later had his law office there for decades. To win the right to build it, Chiofaro — then a 35-year-old newbie developer — outbid blueblood firm Beal Co. to buy a city-owned garage that was key to the project. McCormack recalled Chiofaro wearing his Harvard football jersey to City Hall when he pitched his plan to build two giant towers.

“Don is Don,’’ McCormack said. “He sees one way to do a thing, and he puts on his helmet and off he goes. He’s unorthodox, but he’s not to be underestimated.’’

Chiofaro’s big second act has proved harder. He bought the Boston Harbor Garage with plans for a soaring waterfront skyscraper, but stalled after butting heads with then-mayor Thomas M. Menino. After Martin J. Walsh was elected, Chiofaro’s bold idea again took flight, only to encounter yet more turbulence from the New England Aquarium and other neighbors worried about its impact on the waterfront.

Still, after a decade of battering away, Chiofaro is inching ever closer to his goal. City officials last month approved zoning for a 600-foot tower on the site, which is now under state review. The aquarium sounds increasingly open to a deal. And Chiofaro said he hopes to unveil plans for an actual building — something he’s not done in years — and launch the city approval process later this year.

Meantime, he has also been quietly slogging along in Belmont.

Chiofaro said he’s been thinking about houses in the backyard — where he once raised a pair of pigs — for a long time. Two years ago, he filed plans with the town, and he’s been working through approvals since.

His task has been made harder because Chiofaro, in typical fashion, is pushing the envelope. He wants to build an 800-foot road off of Marsh Street to access the homes; Belmont rules only allow 600 feet. Those extra 200 feet, he said, would let him build five houses instead of three — a lot more money in a neighborhood where newly built homes sell for $2 million or more. But it requires a waiver from selectmen.

On a Monday night in late March, they met to consider Chiofaro’s request. About 100 people came to the hearing, lining the walls and spilling out into the hallway. Most opposed Chiofaro’s plan, and for two hours they said as much, with speaker after speaker raising worries about the road, its effect on neighbors, and the subdivision’s impact on the neighboring 90-acre Mass Audubon Habitat wildlife sanctuary, which seems indistinguishable from Chiofaro’s own woods.

“If you put a house there, you’ll take everything down and it’ll be gone,’’ said one neighbor, Barbara Passero, to applause from the crowd. “This is beautiful, natural land.’’

Chiofaro had fans in the room, too. A man who works at International Place said Chiofaro runs a top-notch building. A longtime family friend talked of Belmont’s need for more housing. And John Mazzone, who has come to know Chiofaro through his support of Belmont sports, told of the builder’s deep roots in the town and his key donation for a new press box at Belmont High School’s football field.

“We’re not talking about ‘some developer,’ ’’ said Mazzone. “We’re talking about Don Chiofaro. This is a guy who loves Belmont as much as we all do.’’

Through it all, Chiofaro sat in the front row, with his oldest son, Don Jr., and a pair of lawyers. When it was his turn, Chiofaro talked about growing up in Belmont and how, to him, open space was the playgrounds and sports fields of the public schools he attended, about how he wants the longer road because it will mean a better project. He talked of the town’s need for more housing, even if the ones he is planning to build would be out of the reach of most home buyers.

“Everybody deserves to live in the best house they can afford,’’ he said. “This is not a place where you get on board and then pull up the ladder and don’t let anybody else in.’’

The selectmen appeared unpersuaded. One opposed the 800-foot road while the other two were noncommittal. They decided to give Chiofaro time to come up with plans for a shorter road.

“There needs to be some sort of compromise here,’’ said Sami Baghdady, one of the undecided selectmen.

Ever the optimist, Chiofaro took the decision in stride. He has a few weeks to work on a new plan, address neighbors’ concerns, and try to win them over.

As he pilots his Mercedes past the sites of his past successes, wearing a baseball hat that reads “Persistence,’’ Chiofaro is confident he will soon turn his vision of five homes in the Belmont woods into reality.

“We’ll get there. We just need to keep talking,’’ Chiofaro said. “I like to say, ‘No’ is the first syllable in ‘Yes.’’’

Tim Logan can be reached at tim.logan@globe.com. Follow him on Twitter at @bytimlogan.