Former U.S. Rep. John Tierney has endorsed Dan Koh in the Democratic primary for Massachusetts’ 6th Congressional District, adding a high-profile name to a growing list of supporters as the race to succeed Rep. Seth Moulton takes shape.
Koh, a former Biden administration official and Harvard College and Harvard Business School graduate, entered the race in October. The seat is opening as Moulton mounts a primary challenge against Sen. Edward Markey. Since launching his campaign, Koh has steadily accumulated endorsements from local and national leaders, including former Vice President Kamala Harris.
Tierney, who represented the district for 18 years, said his endorsement followed conversations with Koh and a close look at the kind of leadership he believes the district needs.
“I think he just epitomizes what this district needs for, you know, representation,” Tierney said. “For me, it starts with the core, right? Are you going to be in the district? Be present. Be around. Are people going to get to have access to you?”
Tierney emphasized constituent service as the foundation of effective representation, drawing on his own experience in Congress.
“We had a rule in our office, a 24-hour period does not go by without the phone call being returned,” he said. “That came from Ted Kennedy — by far, the best constituent office of anybody.”
According to Tierney, Koh reflects that same approach.
“It starts by listening,” Tierney said. “You have a responsibility to tell people why you’re doing something… not because you have to persuade them, but so they know you’re thinking.”
Koh previously served in several senior roles in the Biden administration and worked as chief of staff to former Boston mayor and U.S. Labor Secretary Martin Walsh. He also served as a deputy assistant to former President Joe Biden, an experience he has said left him believing the Democratic Party has lost touch with voters’ day-to-day struggles.
During the interview, Koh said Tierney’s endorsement represents the kind of leadership model he hopes to follow.
“One of the reasons why I’m so honored to have a congressman endorsement is because I think he embodies the mentality that we need to have as Democrats,” Koh said. “We need to be focused on the issues people here in Lynn, Salem, Peabody, all the way to Amesbury to Andover care about — the rising cost of living and how they’re going to provide for their families.”
Koh has also received national attention. Harris endorsed him shortly after he entered the race, calling him “the fighter you deserve.”
Tierney said Koh’s policy knowledge and ability to connect national issues to local impacts stood out.
“I’m impressed with his intellect. I mean, he gets it,” Tierney said. “Whether they’re international, geopolitical, or whether they’re national or regional or state-wide issues, he understands it and the impact that’s going to have on this district.”
Locally, Koh recently secured the endorsement of Lynn City Councilor-at-Large Brian Field, who cited Koh’s readiness to represent the district’s largest city.
“The City of Lynn has been my home and my family’s home for over a century,” Field said. “Lynn is the largest city in the 6th Congressional District, and we need someone strong to represent us in Washington. I believe that Dan is the right choice in 2026. He has the experience to start making a difference on day one.”
Field urged voters across the district to support Koh, calling on “all of my family and friends in Lynn and throughout the entire 6th District to join me in supporting Dan Koh for Congress.”
Both Koh and Tierney stressed the importance of showing up consistently across the district, including in smaller communities.
“You can’t just be there one day a year,” Tierney said. “You have a responsibility to be there.”
Koh acknowledged that trust must be earned.
“I can’t say that. I will just say that I will. I need to show people,” he said. “So I need to double down on my effort.”
Tierney, a Salem native and former chair of the House Subcommittee on National Security and Foreign Affairs, said Koh reminds him of himself early in his congressional career.
“The passion,” Tierney said. “It requires that you have a good breadth of knowledge and information — knowing you don’t have all the answers, but knowing how to go get them.”
For Koh, the role is as much about humility as ambition. “This job is not just fun,” Koh said. “It’s about working your ass off.”
Tierney agreed. “Every day you woke up, and you got a chance to help somebody.”
