Before a fired-up crowd of primarily pink-clad women, Clinton alluded to the controversies the group has faced since a series of videos by anti-abortion activists were released in 2015. Clinton argued that Republicans would "accelerate the assault on access to safe and legal abortion" and that she is the person best positioned to beat them in November.
"I will always defend Planned Parenthood and I will say consistently and proudly, Planned Parenthood should be funded, supported and protected, not undermined, misrepresented and demonized," Clinton said. "As your president, I will always have your back."
Clinton has grown fond of the electability argument in recent weeks because it allows her to both directly hit Republicans -- as she did on Sunday -- and subtly knock Vermont Sen. Bernie Sanders, her chief rival for the Democratic nomination.
"We need a Democratic nominee who will be able to beat the Republicans and get the job done for Americans," Clinton said before asking the audience that "the next president would easily appoint more than one justice to the Supreme Court."
"That fight is not over either. Access to affordable birth control is still hanging in the balance at the Supreme Court," Clinton said. "If a Republicans wins this election and gets the chance to stack the Supreme Court with right wing justices, together they will accelerate the move to take America in the wrong direction on so many issues that you and I have fought for and many Americans take for granted."
Clinton was introduced by Planned Parenthood President Cecile Richards, who said Clinton was the "leader I trust in the White House to make sure women and families move forward."
"In this election, with the attacks on women's health and rights, more than ever before we don't need a friend, a solid vote, a statement, we need a fighter," Richards said about the former secretary of state.
In interview before the event, Richards said that while Sanders has long been a "very solid vote" for their organization, she "could never remember a time where there is a stronger candidate for president [than Hillary Clinton] on the issues that are fundamental to Planned Parenthood."
Sunday's endorsement was the first time the group is endorsing in a presidential primary.
Planned Parenthood plans to spend at least $20 million in this election cycle and Richards said that will include many "grassroots efforts" for Clinton.