Finding individual Giacominis in the West Marin ranch family’s sprawling family tree—all those sisters, brothers, uncles, aunts, grandparents, grandchildren, great-grandchildren, cousins and cousins of cousins—is a complicated affair. But on Sunday, locating Bob Giacomini will be easy.

You’ll find him at the front of the 48th Western Weekend parade, serving in a role he did not anticipate: Grand Marshal.

Once upon a time, among his many civic roles, Bob served as president of the West Marin Lions Club, the primary sponsor of the annual event. He’s kept up with his dues, but he stopped showing up for meetings years ago, which was a very un-Bob-like thing to do.

But there are only so many volunteer commitments one man can keep up with. He needed time for family as well as local and national professional organizations, not to mention the Holsteins at his 700-acre dairy just north of Point Reyes Station, where his daughters make award-winning blue cheese. 

When the Lions Club tried to lure him back to collect his 50-year pin, he never showed up. “I’ve been a Lion since I was 21 years old,” said Mr. Giacomini, who will turn 88 in August. “I went through all the chairs, I was the president, the whole goddamn thing. But sometimes, you’ve got to move on in life. I can’t believe they selected me for this.”

Yet he will be the man of the hour at the June 8 parade, during a festive weekend which this year pays homage to West Marin’s farm-to-table producers. Perhaps he’ll finally be wearing that Lions Club pin.

As a member of one of West Marin’s most storied agricultural families, Mr. Giacomini seemed like a perfect choice, said Madeline Nieto Hope, herself a Lion and a former grand marshal, and a member of the selection committee.

“It’s almost like the universe gave us just what we needed with Bob,” she said. “He should be really proud of what he’s been able to accomplish in his lifetime with his family and his community.”

Like many West Marin ranch families, Mr. Giacomini’s traces its roots to a Swiss Italian border region famous for farming. The first to arrive was his grandfather, Tobias, who set off from Switzerland and arrived in the United States around 1900 after making the arduous journey around Cape Horn to San Francisco. (Ellis Island had shut down temporarily.)

Soon after arriving in California, he settled in Petaluma and met his wife, Celestina, who had just arrived from Italy. There they scraped together enough money to buy a half-dozen cows. “Between the six cows, which they milked by hand, and 400 chickens, they raised six kids,” Mr. Giacomini said. 

Among them was Bob’s father, Waldo Giacomini, who went on to buy the Palace Market in 1938 before purchasing the ranch that is now the site of the Giacomini Wetlands. For years, Waldo’s prosperous ranch was a center of activity in town.

The family lived in the ranch house at the end of C Street, just across from the white barn, and they had an indoor swimming pool where it seemed half the town learned to swim. Waldo also owned a popular deer and duck hunting shack at the southeastern edge of Tomales Bay, close to the old railroad tracks, that drew a crowd of friends each fall. 

While Waldo ran the ranch, his brother Toby started the feed store and a trucking business that was the first in West Marin to transport milk in tankers instead of cans. Bob’s cousin, Toby Jr., today runs the trucking business out of Petaluma, although each one of his 60 trucks still bears the name “Point Reyes” on its side. Toby Jr.’s younger brother, Chris, runs the feed store.

Mr. Giacomini believes telling his family’s story is essential to understanding his own. 

“You’ve gotta start from the beginning of any story,” he said during a recent tour of his ranch. “How did I get here? Well, I got here because my grandfather had five cents in his pocket and came over here with nothing. I wouldn’t be here today without my father and my grandfather.”

As a youngster, Bob worked at the Palace Market while attending Tomales High, where he starred on the baseball team. He occasionally accompanied his dad on 3 a.m. trips to the farmers’ markets in San Francisco, where they would load up on enough produce to stock the store for a week.

After receiving his ag science degree at U.C. Davis, he returned with his wife, Dean, in 1959 to start their own dairy. They ran it for 41 years before opening the Point Reyes Farmstead Cheese Company with their four daughters—Karen, Diana, Lynn and Jill—in 2000.

While Bob was the public face of the dairy, Dean was closely involved from the beginning. “She liked to call herself the C.F.O.,” Jill Giacomini Basch said of her mother, who passed away in 2012. “She was in lockstep on all of the business decisions.”

Mr. Giacomini has since remarried, and he and his wife, Gayle Sarlatte, a retired nurse, make their home in Petaluma. 

Over the years, Mr. Giacomini developed a reputation for embracing innovative sustainable farming techniques. He was one of the first dairymen in West Marin to install a methane digester—a system that breaks down manure, separating it into liquid and solid components used to produce biogas and fertilizer. 

The digester produces half the energy used on the ranch, where Mr. Giacomini will soon install solar panels to provide the remaining 50 percent. The fertilizer is used as compost and as bedding for cows, who are treated like royalty, their milk the key to the success of the cheeses that have put the creamery on the national map.

There’s a special rolling brush attached to the side of the loafing barn where cows can walk over and give themselves a massage. 

“We’re trying to keep the cows as comfortable as possible, and that’s one of the oddball things that we’re using now,” Mr. Giacomini said. “Some cows will stay there a long time because they like it so much.”

Long before the cheese company was born, Bob had been thinking about ways to sustain the dairy, which sold its milk to Clover and other retailers. The state set milk prices, which fluctuated from year to year and did not always keep pace with rising production costs. Developing a product that he could sell directly to the consumer would be crucial.

A turning point came when  Mr. Giacomini began thinking about his retirement. His daughters had grown up, gone to college and embarked on careers off the farm, encouraged by their mother to forge their own paths. “They had no interest in the cows,” Bob said. 

But they did have an interest in business, cooking and quality food, and they did not want to see their parents sell the ranch. After a series of family conversations, they took a leap of faith and formed the Point Reyes Farmstead Cheese Company.

Their timing was right. The artisanal cheese movement had taken root, and Peggy Smith and Sue Conley had recently opened the Cowgirl Creamery, where they developed their own brand and encouraged local dairies to do the same. The U.C. Cooperative Extension offered a cheesemaking course at the creamery, which Mr. Giacomini attended.

“He had such vision, and he was so brave to move from traditional dairy farming and into the cheese business with his girls,” Ms. Conley said. “It was a game changer. They were such big leaders in the dairy community; it was huge that they came and participated.”

After conducting extensive research, the family made some crucial decisions. They would make blue cheese. They loved the stuff, and no other California creamery was making it at the time. They would also put the name of their hometown on the label, given its broad association with things natural and glorious.

It wasn’t long before all the milk produced at the dairy was used to produce Point Reyes Original Blue.

With a commitment to quality and a knack for networking, marketing and sales, the Giacominis quickly penetrated the artisanal cheese market, becoming farm-to-table favorites. Within five years, their cheese production was sustaining the entire ranch. 

Today, they’ve expanded their operation to Petaluma and added several new varieties. They employ about 100 people and produce 2 million pounds of cheese a year.

They’ve been featured on the cover of the New York Times food section and singled out for praise by Oprah Winfrey. They’ve struck deals with Whole Foods, Williams-Sonoma and Trader Joe’s, among other national brands.

Embarking on the effort seemed like a leap of faith, but once they jumped, they were all in. Bob wouldn’t have it any other way. “He just had a bigger vision for life, and he wasn’t going to give up on something,” Lynn Giacomini Stray said of her dad. “He loved the entrepreneurial spirit of trying something new.”

Over the years, Mr. Giacomini was known in the agricultural community as the founder or a member of a wide range of organizations, including Western United Dairymen and the Marin Agricultural Land Trust. In 1997, he was honored as the United States Dairyman of the Year by the World Dairy Expo.

He is curious, practical and a good listener—skills he put to good use back in the early 2000s, when concerns over Tomales Bay water quality were coming to a head. 

Runoff from dairies was regularly forcing oyster operations to shut down after rainstorms. The issue grew especially heated in the early aughts when 170 people fell ill after eating oysters from Tomales Bay. The source of the contamination wasn’t immediately determined, but many were quick to blame the dairies.

“The oyster folks were mad at the dairies, and the dairies were mad at the oyster people and the recreation folks,” said Nancy Scolari, executive director of the Marin Resource Conservation District. “Everybody was pointing fingers at everybody at that time.”

As a member of the Tomales Bay Watershed Council and the Resource Conservation District, Mr. Giacomini helped forge an agreement among parties that found themselves at odds. 

“He’s going to just really listen to all the facts before making a decision or offering an opinion or asking questions,” Ms. Scolari said. “He’s not someone that’s going to say a heck of a lot. But when he does say something, everybody listens.”

At the R.C.D., Mr. Giacomini promoted a wide array of efforts aimed at improving the watershed, from stream restoration and water diversion to rotational grazing, irrigation improvements and putting gutters on barns.

“He was a good steward of the land, and he was willing to talk to oyster growers about ways to improve,” said Terry Sawyer, C.E.O. of Hog Island Oyster Company, who served with Bob on the R.C.D. board. “It’s all about stewardship, community and relationships. He was willing to sit down and participate and do so with a great sense of humor.”

The agricultural landscape has changed dramatically since Mr. Giacomini began his operation, with one dairy after another closing due to economic struggles. Recently, a legal settlement resulted in the closure of most ranches and all the remaining dairies in the Point Reyes National Seashore.

Back in his early days,  Mr. Giacomini and his dairy buddies would meet for breakfast each morning at the Pine Cone Diner, now the Side Street Kitchen. They had a key to the place, and they’d make their own coffee. A roll of the dice would determine who picked up the tab. At the end of the day, they’d meet up at the Old Western and knock back a few drinks.

Bob is the last member standing of that old group. Most of the others have passed away and two of his closer friends have left town after the settlement. “The McClures and the Kehoes are two of my better friends from out at the point, and they’re the two that have already left,” he said. “There’s only three dairies left out here now, and that’s ourselves, the Taylors and the Straus family.”

He views the changing landscape philosophically. “You never know what’s around the corner right here, because there’s always something in life that has to change,” he said. 

After a lifetime of innovation and success, Mr. Giacomini still comes across as a humble man who is grateful to be recognized for hard work. Just months shy of his 88th birthday, he still shows up at the ranch most days.

“I love what I do, and the worst thing I could ever do is sit at home in a rocking chair,” he said. “I’d be dead in a month if I did that. It’s been a good life. I wouldn’t change it for anything.”