Her likely general election rival, Donald Trump, continued his months-long effort to win over the Republican base, with events wooing top donors and evangelical voters.
With the primary contests all but over, a series of top Democrats formally announced their support for Clinton, headlined by the glowing endorsement of President Barack Obama on Thursday.
Within hours, Vice President Joe Biden and Massachusetts Sen. Elizabeth Warren joined that effort, both backing Clinton and signaling to many of Sanders' supporters that it's time to unite around the party's presumptive nominee. Clinton and Warren met privately for about an hour Friday morning at Clinton's home in Washington, intensifying speculation that the progressive stalwart may be tapped for the vice presidency.
"If you really want to electrify the base you've got to get somebody who's been speaking to the base and is going to turn the base out," said Rep. Keith Ellison, D-Minn., one of Sanders' top supporters in Congress. He said he and other progressives would be thrilled if Clinton tapped Warren for her ticket.
Democrats in Washington are eager to unite their party against Trump and avoid a lingering intraparty spat. Primary rival Bernie Sanders, who's vowed to take his political revolution to their national Democratic convention in July, has been stressing his determination to defeat Trump, perhaps signaling that he may exit the race or at least shift his focus away from Clinton after the final primary election next Tuesday in Washington, D.C.
On Friday, he retreated to his home in Burlington, Vermont, to plot his next steps.
Clinton, meanwhile, delivered her first speech since becoming the presumptive nominee, addressing advocates at Planned Parenthood, the women's health organization and abortion provider. The nonprofit was a strong champion of Clinton in the primaries, giving her its first endorsement in their 100-year history.
Describing Trump as someone who "doesn't hold women in high regard," Clinton launched into an unabashedly feminist attack on her GOP rival, arguing he would take the country back to "when abortion was illegal, women had far fewer options and life for too many women and girls was limited."
"When Donald Trump says, 'let's make America great again,' that is code for 'let's take America backward,'" she told the cheering audience.
Trump, who has also faced resistance from corners of his party, addressed a gathering of conservative evangelical voters at the Faith & Freedom Coalition's "Road to Majority" conference not long after Clinton spoke.
Facing criticism for suggesting a judge's Mexican heritage biased him in a case against the now-defunct Trump University, Trump struck a more welcoming tone.
"No one should be judged by their race or their color and the color of their skin," he said. "We're going to bring our nation together."
Reading mostly from teleprompters, he declared Clinton "unfit to be president" while vowing to "restore faith to its proper mantle" in the U.S.
As he took the stage, Trump boasted of the support he received from evangelicals in the Republican primary and touted his opposition to abortion rights and commitment to religious freedom — issues he rarely discusses in other settings. Seizing on social issues, Trump claimed Clinton would appoint "radical" judges who would "abolish" the Second Amendment and "destroy the rule of law."
In a new dig against her email scandal, Trump proposed "tough new ethics rules to restore dignity of the office of the secretary of state" and challenged Clinton to drop her support for increasing refugee admissions and instead support "a new jobs program for our inner cities."
It was one of several examples of Trump's burgeoning populist attacks against Clinton, whom he painted as indebted to big money. He claimed her immigration, education and trade policies would harm working families and "plunge our poor African-American and Hispanic communities into turmoil and even worse despair."
"Her policies will be a crushing blow to all poor people in this country," he said.
He also accused Clinton of failing to understand the gravity of the risk posed by Islamic extremism, and faulted her for wanting to allow more Syrian refugees into the country.
"Hillary will bring hundreds of thousands of refugees, many of whom have hostile beliefs about people of different faiths and values and some of whom absolutely and openly support terrorism in our country," he claimed. "We have to temporarily stop this whole thing with what's going on with refugees where we don't know where they come from." Clinton has proposed allowing 65,000 Syrian refugees into the country each year.
His speech was interrupted by several protesters, including one woman who screamed "Refugees are welcome here!" as she was escorted out of the room.
Many evangelical and conservative leaders remain deeply skeptical of Trump's candidacy —a resistance that was underscored by the speakers who proceeded him on Friday.
Former rival Carly Fiorina, who spoke immediately before Trump, failed to mention her party's presumptive nominee's name a single time during her remarks, which heavily criticized Clinton.
Meanwhile, in his long-expected endorsement, President Barack Obama pointed to Clinton's grit and determination but also called for "embracing" Sanders' economic message, which has galvanized liberals and independents. Obama sought to reassure Democrats that Clinton shares their values and is ready for the job.
The president plans to campaign next week with Clinton in Green Bay, Wisconsin, marking his first major foray into the 2016 campaign.
"It was a wonderful, meaning endorsement in every way," said Clinton, sipping an iced chai, during a stop at a muffin store in Washington.