“I think it’s the lens I’m looking at issues through: being a mom and the importance of safeguarding the future of our kids,” Grossman said of pitching herself to Fourth Congressional District voters. “Our country is on fire, and good, logical people need to step up to work together and make progress on the issues that we all care about.”

Grossman, 39, plans to formally announce her campaign Tuesday, with a focus on prescription drug prices, gun control, and climate change, Those are core Democratic Party issues that, she said, are driven by her experience as a mother of two school-age children.

Becky Walker Grossman — a Newton city councilor and former prosecutor whose father-in-law once chaired the Democratic National Committee — is running for the seat held by Representative Joseph P. Kennedy III, she said Monday, making her the first candidate to enter what’s expected to be a crowded Democratic primary since Kennedy pivoted to a Senate run.

Kennedy, 38, the Newton Democrat who has held the seat since 2013, capped weeks of speculation on Saturday when he formally launched a primary challenge to Senator Edward J. Markey. The announcement, while foreshadowed for days, is expected to open the door to other Democrats to make official their own plans in the Fourth District, which winds through 34 municipalities from Boston’s western suburbs to the South Coast.


Ihssane Leckey, a self-described democratic socialist from Brookline, declared before Kennedy’s announcement.

Grossman’s entrance comes two years after she first won election to the Newton council. A graduate of both Harvard Law School and Harvard Business School, she is a former Middlesex assistant district attorney, and pointed to the experience of her 69-year-old mother, whose battle with a rare autoimmune disease has helped shape her views on health care policy. It’s included seeking out prescriptions that, at times, have cost as much as $1,000, Grossman said.


“It’s been a tough journey for our family,” she said.

Grossman is the daughter-in-law of Steve Grossman, the former state treasurer and national Democratic Party chairman, who could help boost her profile among donors in what could be an expensive race.

Grossman said Monday that she expects her family to be “cheering me on,” but Steve Grossman said in a separate interview that he plans to take no formal role in her campaign.

“I fully expect to be judged by the people of the Fourth District by what I have to offer,” Becky Grossman said.

Her foray into the race is unlikely to be the last in the coming weeks. State Treasurer Deborah B. Goldberg has filed paperwork with federal elections officials, but advisers have said she remains undecided on running. Jesse Mermell, a former Brookline selectwoman, stepped down as president of the Alliance for Business Leadership and has begun assembling a team of advisers in preparation for a campaign, according to a source close to her.

They’re two of several with Brookline ties weighing a decision, including state Representative Tommy Vitolo, who was elected last November, and Dave Cavell, a former speechwriter to President Obama.

State Senator Paul R. Feeney, of Foxborough; Newton City Councilor Jake Auchincloss; and state Representative Patricia A. Haddad, a Somerset resident and the House’s third-ranking Democrat, have said they’re also considering running.

It’s unclear what the Republican field could look like.


Matt Stout can be reached at matt.stout@globe.com.