John Abrams, who founded South Mountain Company in 1975. — Ray Ewing

Even before John Abrams, founder and former CEO of South Mountain Company, announced his retirement late last year, the question of his successor was highlighted in a plan titled the Avalanche Scenario. The plan outlined what would happen if Mr. Abrams, an avid outdoorsman, were to be buried in an avalanche.

This January, the firm’s former COO, Deirdre Bohan, took on the CEO role sans hiking accident, but her climb to the top took some persuasion.

“Deirdre had always made it absolutely clear the one thing she did not want to do is be CEO,” Mr. Abrams said with a laugh during a recent interview. The pair were sitting in the front conference room at the South Mountain headquarters, a warm, wooded compound in West Tisbury. The firm, whose work encompasses architecture, design, building, engineering and solar installation, began in 1975 when Mr. Abrams moved to the Island and started building houses upon request.

South Mountain has grown since then into a 38-person team.

New CEO Deirdre Bohan. — Ray Ewing

“It felt like a tremendous responsibility,” Ms. Bohan explained. “Not just for caring for our staff but also for their families. That’s really how we look at it.”

Like many at the firm, Ms. Bohan began at the ground level. She first joined South Mountain as a bookkeeper in the mid-1990s, when the company operated out of a building at the Allen Farm Sheep and Wool Company in Chilmark.

“It was incredibly old school,” Mr. Abrams said. “We were doing everything by hand. Our last bookkeeper left because she couldn’t handle it. Deirdre walked in and moved everything to QuickBooks in two months . . . . And she just started asking me, ‘What can I do next?’”

From there, Ms. Bohan worked her way up to becoming the company’s taskmaster, she said, taking her knack for technology, organization and efficiency and applying it companywide. The pandemic proved to be her largest test thus far, with the company shutting down for several weeks before transitioning to a remote and then hybrid model. The current system Ms. Bohan helped create has employees come into the office at least two days a week, with a sizeable portion opting to come in every day.

South Mountain's workshop. — Ray Ewing

“We ended up with a greater amount of trust to get done what we needed to do,” Ms. Bohan said.

Ms. Bohan said she was initially more comfortable in roles like these, tackling issues behind the scenes and working with systems rather than people. Over the course of their 25-year partnership, Mr. Abrams and Ms. Bohan both observed her grow into a leadership role.

“Generosity of spirit . . . that didn’t come to me so naturally in the past and now it does,” she said. “That is what I have experienced and learned over the years.”

“She’s changed so much,” Mr. Abrams added. “She’s a completely different person.”

A workers' cooperative model was adopted in the late 1980s. — Ray Ewing

Still, Ms. Bohan acknowledges that South Mountain operates best as a team, which is why she is joined by an executive board of four other employees of South Mountain: Ryan Bushey, Rob Meyers, Newell Isbell Shin and Siobhan Mullin. It’s a leadership structure that emphasizes the collaborative approach Mr. Abrams has always sought to espouse, she said.

“We’ve all worked with each other for so long and we’re very aligned,” Ms. Bohan said. “There’s no competition.”

It’s also an approach embedded in the very structure of the company, which follows a workers’ cooperative model. Rather than giving select partners a financial stake in the company, worker-owned co-ops allow employees of all levels to own a share.

“I thought it was a formality,” Mr. Abrams said of the move to a worker-owned model, which took place in 1987. “Nothing could have been further from the truth. It changed how involved people felt, how invested they were.”

There are currently 22 co-owners in the company; employees become eligible after completing a five-year waiting period. The worker co-op model, a rarity when Mr. Abrams adopted it, has gained steam in recent years. Mr. Abrams’ next venture as a management consultant will help spread his model to the rest of the business world.

The company's headquarters is in a wooded West Tisbury compound. — Ray Ewing

“There are business owners approaching retirement who are also facing questions about succession,” he said. “They want to make sure the company stays in good hands after they leave and instead of giving it to an outsider, it’s a way of rewarding the people who built that scaffolding with you.”

Heading into her new position, Ms. Bohan said she won’t be trying to keep it business as usual because, as she notes, the company is always open to change. After several retirements, South Mountain has seen an influx of young, new hires and Ms. Bohan said she has made it her mission to unlock their potential, the same way Mr. Abrams unlocked hers so many years ago.

“What struck me about this company when I first joined at 20 [years old] was the ability to have an idea and have it heard . . . to have a voice right away,” Ms. Bohan said. “From day one you feel like you can be a part of it.”