DERRY, N.H. — Former first lady Barbara Bush made her way slowly into a middle school gymnasium with her son Jeb by her side, as the Beach Boys’ “Barbara Ann’’ blared through the speakers.

“I didn’t really plan on this,’’ she joked, wearing a vibrant green shirt and black scarf. But she did not hesitate to deliver her message:

“Jeb is the nicest, wisest, most carrying, loyal, disciplined . . . ’’ she said. “But he’s not a bragger. We don’t allow that. He’s everything we need in a president.’’

Every seat in the room was filled and people stood crammed into corners, straining to see the matriarch of a political dynasty and one of its heirs.

Jeb Bush, who has been struggling to break out of a crowded Republican primary field, stood by affectionately as his 90-year-old mother spoke, noting when she was done: “Wow. Mom, my crowd sizes normally are not this large. I wonder why.’’

In the final days of his campaign, Bush — trailing in the polls — has sought to connect with voters on a more personal level. It doesn’t get more personal than mom, and Barbara Bush remains popular — sometimes even when her sons are not.

“She’s like America’s grandmother,’’ said Charlie Black, a leading Republican strategist who served as an adviser to both Bush presidents. “She’s one of the most popular women in America.’’

Barbara Bush, given her age, is no longer going from polling place to polling place to shake the hands of supporters and say thank you on primary day, as she did for her husband in 1988. So her presence on the campaign will be more strategic, analysts say.

“She’ll pick her spots just because, again, at her age you can’t expect her to campaign all the time,’’ Black said.

Barbara Bush has been here before — not only to help her husband in the 1980s and 1990s, but again for her eldest son in 2000.

Jeb Bush has staked much of his campaign on the first-in-the-nation-primary state, where he only recently broke out of single digits in some polls. After placing sixth in the Iowa caucuses, a poor finish in New Hampshire could spell the end of Bush’s campaign — and another generation of Bush family members’ bids for national office.

Barbara Bush was there Thursday night in a effort to make sure that does not happen.

Kevin Olvaney, a longtime Bush family supporter from Londonderry, said he didn’t know Barbara Bush was going to take the stage that evening, saying “Oh, wow!’’ when he found out. “Maybe that will help him.’’

Barbara Bush first hit the trail in New Hampshire with her husband, former president George H. W. Bush, when he ran for president in 1980 and lost.

She returned when another son, former president George W. Bush, struggled and lost the New Hampshire primary to John McCain in 2000.

“She speaks her mind frankly, and people in New Hampshire like that,’’ said Steve Duprey, a Republican National Committee member from the state.

Joe Corda and his wife, Jane, said Bush was on their short list of candidates but they had yet to make up their minds completely.

Their hope was that Bush’s speech Thursday night would help solidify his support. Fans of the Bush family, they got the extra perk of hearing his mother speak.

“It’s not George, but we’ll take it,’’ Jane Corda of Londonderry said.

Tom Rath, a former state ­attorney general who has been involved in politics for more than 30 years, said there’s a tendency with the Bush campaign to run from the family’s legacy, but Barbara Bush is a reminder of the clan’s positive aspects.

Bush fully embraced his family’s legacy on Thursday night.

“Yeah, I’m part of the establishment because I’m Barbara Bush’s son. I embrace that each and every day. That doesn’t bother me a bit,’’ he said. “I’m proud of my dad. I’m proud of my brother. I’m proud of being a Bush.’’

With his unique family position, Bush acknowledged that he has long had a “front-row seat’’ to the national and world stages.

“I know how to do this,’’ he said during a town hall meeting that lasted more than an hour, in which he outlined his plan on Social Security, immigration, education, foreign affairs, and addiction and recovery. “It is not about trash talk.’’

Barbara Bush became more accustomed to life in the public eye over the years. After George H.W. Bush lost Iowa in 1988, she recalled an “awful’’ plane ride to New Hampshire in her 1994 memoir. Bush’s campaign manager and the staff “were down in the dumps.’’

“I finally said that they must cheer up,’’ she wrote. “How could they expect George to campaign with so many people around him singing the blues.’’

Four years later, she filed her husband’s declaration of candidacy to appear on the New Hampshire primary ballot.

And in 2000, when her son was in a virtual dead heat with McCain, she appeared at a town hall meeting with the rest of the family and told the crowd: “Thank you for all you’re doing for my boy.’’

Barbara Bush conveyed a similar message for a different son Thursday night, saying that New Hampshire values are the same that “we Bushes believe in.’’

Then she called him “the next president of the United States.’’

Akilah Johnson can be reached at akilah.johnson@globe.com. Follow her on Twitter @akjohnson1922.