Kamala Harris pledged to earn the votes of young people this election, as the vice-president and newly elevated presumptive Democratic nominee rides a gen Z-powered wave of online “Kamalove” .

In a pre-taped virtual address to attendees of a two-day youth voter summit in Atlanta, Harris said she had been elected the first female vice-president of the United States in 2020 “because young voters showed up”. She touted “historic progress” made by the Biden-Harris administration on combating gun violence and climate change, all of which she said was again “at stake this November”.

“We know young voters will be key, and we know your vote cannot be taken for granted,” she said. “It must be earned, and that is exactly what we will do.”

In the days since Joe Biden ended his presidential re-election campaign and endorsed the vice-president for November’s race against Republican nominee Donald Trump, young supporters have flooded social media with coconut tree video cuts and “brat summer” memes – a reflection of the way her campaign has jolted a presidential race many Democrats were afraid was slipping away.

In an interview on the sidelines of the summit, progressive US representative Pramila Jayapal, said the level of enthusiasm she has seen for Harris in the last six days – especially among young people – was “undeniable”.

“I have not seen anything like this,” Jayapal, chair of the Progressive caucus, which was divided over the question of whether Biden should step aside, said. “The closest was probably Barack Obama.”

Citing the Harris campaign’s record fundraising and a surge of early support, Jayapal said: “But this is even more than that – just the amount of money that’s been raised. The fact that it’s come from grassroots donors, the fact that it’s first-time donors, the volunteers, the voter registration, it has really been palpable.”

Jayapal said Harris, who is poised to become the first woman of color to lead a major-party presidential ticket, had a unique opportunity to excite young people as well as Black and brown voters. Harris was also a strong messenger on issues that matter to young people, especially abortion rights, she said.

“On every level, including the fact that she is a prosecutor and she will prosecute the case against a convicted felon, I think this is going to be a candidate that can take us to victory,” Jayapal said.

Doug Jones, a former Alabama senator and a close ally of Biden, said Democrats were desperate to unite after a painful few weeks.

“It has moved not just with lightning speed, but with an enthusiasm that I’ve never seen,” he said in an interview at the conference. “It is extraordinary.”

Many young people have expressed hope that Harris will distance herself from Biden’s approach to Israel’s war in Gaza.

During a meeting on Thursday, the vice-president said she implored Benjamin Netanyahu to accept a ceasefire deal that would pause the fighting in Gaza and release hostages. In comments afterward, Harris emphasized Palestinian suffering while also recognizing Israel’s right to defend itself.

“We cannot look away in the face of these tragedies,” Harris said this week. “We cannot allow ourselves to become numb to the suffering. And I will not be silent.”

Jayapal, who was among the roughly 100 House Democrats who boycotted the Israeli prime minister’s address to Congress this week, said it would be “complicated” for Harris to chart her own course while still serving as vice-president.

“I know that she feels a deep empathy for Palestinians,” said Jayapal, who said she had spoken recently to Harris about the issue. Pointing to Harris’s remarks after meeting with Netanyahu this week, the Seattle Democrat said: “I think she was trying to signal that she wants to take a different course – that she wants to perhaps consider things that President Biden hadn’t considered or had decided not to do.”

Jayapal noted that it wasn’t just young people and Arab and Muslim Americans who were pushing the administration to change its approach. Black faith leaders and labor groups have also joined calls for the US to stop sending offensive military aid to Israel.

“I believe she is listening to all of that,” Jayapal said. “How she actually moves, we’re going to have to see.”

Jayapal also weighed in on Harris’s search for a running mate. Her preference is Tim Walz, the Minnesota governor, a strong supporter of labor who Jayapal believes would help Democrats hold the midwest. Walz is one of more than a half-dozen candidates viewed as potential running mates.

Trump made his own pitch to young conservatives in Florida, at a conference on faith hosted by the far-right youth advocacy group Turning Point Action. In his remarks on Friday, Trump vowed to “protect Christians in our schools and our military and our government and our workplaces and our hospitals, in our public square”.

He also told the gathering that they would not “have to vote again” if they return him to the presidency in November’s election.

“Christians, get out and vote! Just this time – you won’t have to do it anymore,” he said, denouncing the vice-president as “incompetent”.

Harris, speaking earlier on Saturday at a private fundraiser in Pittsfield, Massachusetts, called the attacks on her by Trump and his running mate, Ohio senator JD Vance, “just plain weird”.

Recent polling had shown Republicans making gains with voters under 35 amid widespread disillusionment with the state of American politics, its institutions and its leaders. However, an Axios/Generation Lab poll conducted after Biden stepped down, shows Harris opening a 20-point lead over Trump with young voters.

Youth-led groups that have been calling on Democrats to do more to invest in young people are hopeful Harris can harness this new energy around her campaign. Already, her campaign has leaned in, embracing an excitement they have branded the “Kamalove”.

“The thing that’s creating the energy here is Vice-President Harris and the hope that she’s been giving young people and the vision that she wants to accomplish for us,” said Marianna Pecora, the communications director for Voters of Tomorrow, which is hosting the Atlanta Year of Youth summit. “Young people are excited and they’re energized and they’re finding politics to be a joyful thing, something that they want to pay attention to for the first time in a long time, and I don’t think that’s momentum that can die with a meme.”

A handful of new polls this week showed Democrats, with Harris at the top of the ticket, gaining a few points against Trump, with the national race against the former president now neck-and-neck.

At a private fundraiser in Massachusetts on Saturday, Harris characterized herself as the “underdog” to Trump in the presidential race. “We are the underdogs in this race. Level-set, OK. We are the underdogs in this race, but this is a people-powered campaign,” she said.

Voters of Tomorrow, a liberal gen Z-led organization, recently joined with a coalition of 17 youth groups to unite behind Harris. The newly formed alliance aims to boost Harris in the final 100-day stretch before election day.

On 21 July, after Biden endorsed Harris, Voters of Tomorrow recorded its best fundraising day, raising nearly $125,000. It has also been flooded with new applications and requests to start new chapters.