Is this the guy to take on Partners HealthCare?

Kevin Tabb is chief executive of Beth Israel Deaconess.Globe staff

When Kevin Tabb took over as chief executive of Beth Israel Deaconess Medical Center more than five years ago, he came with an impressive resume — except for one notable gap: Tabb had never before run a hospital.

If he was intimidated by his new responsibilities as head of the prestigious Boston teaching hospital, it didn’t show. In fact, Tabb had something even bigger in mind. Soon after he arrived in town, he had dinner at a Chestnut Hill steakhouse with Dr. Howard R. Grant, chief executive of what was then called Lahey Clinic. On the menu: a possible merger.

The hospital leaders were intrigued by the idea that they could create a health care system with enough clout to go up against market leader Partners HealthCare. The possibility of a Beth Israel Deaconess-Lahey merger had been floated before, but Tabb continued the talks with Lahey, on and off for years.

Finally, in January, Beth Israel Deaconess and Burlington-based Lahey Health announced they had signed letters of intent to merge. It would be the largest merger of Massachusetts hospital systems since 1994, when Massachusetts General and Brigham and Women’s hospitals joined to create Partners. The deal needs approval from regulators, and both sides are working out details, but they have agreed that Tabb, 53, would run the new combined company.

If it goes through, Tabb will face a huge challenge — mergers can be costly and complicated, messy marriages of workplace cultures and management styles. But nearly a dozen people who know or have worked with Tabb say his varied experience, communication skills, sharp focus on data and results, and ability to navigate changes in the health care industry have prepared him for the task.

Colleagues say he thinks strategically, always examining industry trends and calculating how to adapt. He’s focused more on what’s happening outside the walls of the 651-bed teaching hospital in the Longwood Medical Area than on what goes on inside, according to people who have worked with him.

“There are two types of leaders,” said Dr. Tom Delbanco, a longtime physician at the hospital who calls Tabb a friend. “There are those that put most of their energy into the day-to-day workings of the institutions, and there are others who would rather work strategically on where the hospital is placed and how it might prosper in an ever-changing external environment. Kevin falls into the latter category, and he’s very, very good at that.”

That, apparently, was the idea behind Tabb’s hiring this year of a new president to oversee operations at the medical center — it allows him to concentrate on strategy and fund-raising.

Tabb — who didn’t speak with the Globe for this story — came to Boston the year after the Affordable Care Act was signed into law. The federal overhaul prompted many health care leaders to pursue mergers that could give them more leverage to weather major policy changes. Tabb quickly started working on his own deals. In 2012, Beth Israel Deaconess acquired Milton Hospital , and in 2014 it added Jordan Hospital in Plymouth.

The Beth Israel Deaconess system generates $2.5 billion in annual revenue and includes four hospitals, 1,200 doctors, and about 14,000 employees.

Tabb also forged partnerships through the Beth Israel Deaconess Care Organization, or BIDCO, a contracting network. BIDCO has grown to include eight hospitals and nine physician groups. It negotiates with insurers jointly and runs an accountable care organization, which is a network of health care providers that receive set payments from insurers to manage patient care.

But even as Tabb signed those pacts, a potential merger with Lahey was still percolating in the background. He and Grant returned to the table to talk about it again and again.

Tabb has yet to speak publicly about the pending merger. In a January statement, he said what any hospital executive touting the benefits of a consolidation deal might be expected to say: It “would offer patients comprehensive, coordinated services . . . and help contain rising health care costs.”

Tabb has an unusual background for a Boston health care executive. He grew up in Berkeley, Calif., then moved to Israel, where he joined the military. He attended college and medical school at Hebrew University in Jerusalem.

In Israel he met his wife, Caron, an abstract painter, and he stayed for 18 years before returning to the United States to work in health care technology, including a stint running a unit of General Electric Co.’s health care business. He hasn’t practiced as a physician since completing his residency in 1999.

After GE, Tabb went to Stanford Hospital & Clinics, where he moved up the ranks to become chief medical officer. He became known for using data and metrics to persuade doctors to improve the quality of their care. It was a politically sensitive job, but he “turned people who could be antagonists into allies,” said Dr. Alan M. Garber, the provost of Harvard University and a former colleague of Tabb’s at Stanford.

Tabb oversaw an upgrade of Stanford’s patient record software system years before many other hospitals modernized their technology systems, said Dr. Philip A. Pizzo, former dean of Stanford’s medical school.

“Kevin had a lot of vision,” he said. “He understood where academic medical centers were going.”

Tabb’s work at Stanford was noticed by the board of Beth Israel Deaconess, which was looking for a new leader in 2011 following the resignation of the chief executive, Paul Levy.

“Kevin was at Stanford, he had no exposure to Harvard at all, but he showed up at the interview so well prepared and did so much work, he was clearly the best candidate,” said Stephen Kay, former chairman of the hospital board that hired Tabb. “Our only reservation about him was he did not know Boston and did not know Harvard. In a sense, we took a shot. It worked out.”

Tabb may have been an outsider, but he didn’t act the part. While he seems to prefer staying out of news stories, he made a point of meeting people in Boston’s health care scene and spoke with enough authority to impress industry veterans.

Christina Severin, former chief executive of the BIDCO network, met Tabb after he had been in Boston for about a year. “He struck me as kind of a local person,” Severin said. “He knew everybody already.”

In meetings, Tabb became known for his genial but direct manner, and for listening to others as much as he talks, several people said.

He even befriended one of his biggest professional rivals, Massachusetts General Hospital’s president, Dr. Peter L. Slavin. The two chat about health policy and tech gadgets (like which one is carrying the latest smartphone), and they exchange vacation tips. Sometimes they and their wives get together for dinner or a movie.

But that relationship was strained in 2014 when Tabb joined the leaders of Lahey, Tufts Medical Center, and the Atrius Health doctors group to campaign against an expansion plan by Partners, Mass. General’s parent company. Partners wanted to take over South Shore Hospital in Weymouth and Hallmark Health System’s two hospitals in Medford and Melrose.

Its competitors hired lawyers and public relations firms to argue that the deals were anticompetitive and would drive up medical spending, because Partners is already a high-priced system. The state Health Policy Commission and Attorney General Maura Healey took a similar position. The backlash escalated, eventually forcing Partners to scrap its acquisition plans.

Slavin said he and Tabb have put the episode behind them. They still talk on a regular basis, but they’re careful not to get too specific about work. “There’s some things we can’t talk about,” Slavin said. “We’re competitors in the market.”

Like other people in demanding jobs, Tabb starts his work days early. The father of two finds time to run in the mornings, a routine he started after deciding he wanted to lose a few pounds. Last summer, he ran his first half marathon. But he hasn’t cut out carbs: He brews his own beer at home.

Now Tabb is in a marathon of a different kind — it will take months, or years, to complete the deal with Lahey. State officials must first be convinced that it will benefit consumers, not create another behemoth that will reduce competition and further drive up costs.

But one obstacle that stopped the two organizations from coming to terms in the past has been removed: Lahey’s Grant has agreed to step down once the merger goes through.

“We feel confident,” said Ann-Ellen Hornidge, a member at Mintz Levin who chairs Lahey’s board. “One of the things we’ve built confidence in is Kevin’s leadership. He’s the right person to lead the new system. That always takes some time.”