One of Dorchester’s largest private employers is a Port Norfolk-based company that was founded in 1969 by two men who gave it their names: Sullivan & McLaughlin, better know by their current handle “SullyMac.”

The electrical construction and maintenance firm is now under the ownership and management of a second generation of McLaughlins, led by president John McLaughlin and his brother-in-law, executive vice-president John Rudicus. Together, with company CEO Dennis Miller, the two have managed to build SullyMac into one of the region’s premier contracting firms with a staff of more than 500 union men and women, most of them affiliated with another Dorchester institution, IBEW Local 103.

“We’re both very proud that it’s a Dorchester-based, family-run business that has a great feel to it,” said Rudicus, who is married to John McLaughlin’s sister Katie. “This neighborhood has been great to us.”

SullyMac has been a good neighbor as well. Originally situated on Dorchester Avenue, first in an old horse stable near Peabody Square and then in space closer to Freeport Street, the company needed to relocate as business picked up in the late 1990s. They moved for a short time to Quincy and considered moving even farther afield to a suburban locale with less expensive options. But in 1999, when the SullyMac team discovered a building on Lawley Street that was once used as a warehouse for the maritime manufacturer of the same name, it seized the opportunity to move back to Dorchester.

“It just made sense to us,” said McLaughlin, whose grandfather, Hugh McLaughlin, was an Irish immigrant who worked in maintaining St. Peter’s Church and lived on Meetinghouse Hill where he raised his family, including John’s dad. “Everyone you knew and did business with were here and we had so many of our employees from here.”

The company has restored the old ship-building factory into primarily office space, with some storage room set aside for equipment. The company has added new space in recent years on nearby Tenean Street, buying a factory once used to make Sunbeam bread products.

Tag team members McLaughlin and Rudicus say that the firm’s growth and success – it expects to bill in excess of $150 million this fiscal year – has been a result of smart hires and astute sales strategies. When John and his brother Hugh first came to work with their dad in 1991, there were only 12 full-time employees and half of them would often be idle, depending on seasonal work in the field. They added a service division— providing specialized repairs and installations for bank ATM machines, for example— which allowed them to add more staff and keep them employed more often.

“There was an ebb and flow to the work and we noticed that half of the guys would be out of work,” said Rubicus. “We said, ‘It doesn’t have to be that way.’”

McLaughlin and Rudicus also forged better relations with local labor leaders, a primary one being Michael Monahan, longtime business agent at IBEW Local 103. In the early days of SullyMac, McLaughlin says, the employees had resisted joining the local. But as years progressed— and the union president became enamored of John’s father in particular— the relationship softened. These days, McLaughlin directly links the growth of SullyMac to the contemporaneous expansion of the union’s reputation and membership.

“Mike Monahan was a fan of my dad and we built a better relationship,” said John. “The shift in our attitudes started that trend. I would say that Michael Monahan’s success and the success of this company really parallel one another. He’s been a progressive and dynamic leader.”

SullyMac has plugged into major clients like Fenway Park — and became a more well-known entity in the public’s mind by sponsoring Friday Nights at Fenway and a generous donor to the Jimmy Fund. They also joined an effort coordinated by Local 103 to send electrical workers to Haiti to help build that country’s first teaching hospital, a state-of-the-art 300-bed facility that is now open in Mirebalais. SullyMac also oversaw the design of the solar panel array that is on the roof and powers the entire building. Volunteers from the company flew down to Haiti and installed everything from light fixtures and ceiling fans.

Closer to home, SullyMac is plugging into the civic fabric of Dorchester as well. The firm’s bucket trucks are frequently called upon to assist in seasonal decorations along Dorchester Avenue, for example.

Whether SullyMac’s ownership will extend to a third generation remains to be seen. Rudicus and McLaughlin have six children between them— none of them old enough yet to be employed there. For now, the focus is on recruiting and keeping top-notch talent among the union electricians. “We developed that skill set and we do a fair amount of aptitude testing,” said Rudicus.

McLaughlin, who is a salesman, not an electrician, said the company still employs the same philosophy that his father used to good effect. “He had 12 phenomenal employees and they all worked for John McLaughlin. It was a philosophy that stuck with us— that we’re going to trust you to do this.”