Post-2016 election activities

In their respective capacities as a former president and a former first lady, Bill and Hillary Clinton attended the inauguration of Donald Trump with their daughter, Chelsea. The morning of the inauguration Clinton wrote on her Twitter account, "I'm here today to honor our democracy & its enduring values, I will never stop believing in our country & its future."

Clinton delivered a St. Patrick's Day speech in Scranton, Pennsylvania, on March 17, 2017, referring to reports of her being seen taking walks in the woods around Chappaqua following her loss in the presidential election. Clinton indicated her readiness to emerge from "the woods" and become politically active again.

On March 24, 2017, after the postponement of a Congressional vote to repeal the Affordable Care Act, Clinton labeled the day "a victory for the 24,000,000 people at risk of losing their health insurance" and warned of an ongoing battle to maintain coverage. She went on to call the American Health Care Act "a disastrous bill" during a San Francisco speech four days later. After the House narrowly passed the American Health Care Act on May 4, Clinton dubbed it a "shameful failure of policy & morality by GOP". On June 23, the day after Senate Republicans revealed a draft of their healthcare reform legislation, Clinton tweeted, "This is a critical moment about choosing people over politics. Speak out against this bill."

Clinton commented that she would not seek public office again in April. On April 6, in response to the Khan Shaykhun chemical attack, Clinton said the U.S. should take out Bashar al-Assad's airfields and thereby "prevent him from being able to use them to bomb innocent people and drop sarin gas on them".

In May 2017 Clinton announced the formation of Onward Together, a new political action committee that she wrote is "dedicated to advancing the progressive vision that earned nearly 66 million votes in the last election". In a June 2017 appearance at a Baltimore fundraiser for the Elijah Cummings Youth Program in Israel (ECYP), Clinton condemned the 2017 Portland train attack: "When violence motivated by hatred from, Portland, Oregon, to College Park, ends the lives of young Americans, this program's mission of spreading tolerance is more urgent than ever." On June 14, after the Congressional baseball shooting, Clinton tweeted, "2 sides take the field tomorrow, but we're all ultimately on one team. My thoughts are with the members of Congress, staff & heroic police."

Clinton's third memoir, What Happened, an account of her loss in the 2016 election, was released on September 12, 2017, by Simon & Schuster, in print, e-book, and as an audiobook read by the author. A book tour and a series of interviews and personal appearances were arranged for the launch. What Happened sold 300,000 copies in its first week, less than her 2003 memoir, Living History, but triple the first-week sales of her previous memoir, 2014's Hard Choices. Simon & Schuster announced that What Happened had sold more e-books in its first-week than any nonfiction e-book since 2010. As of December 10, 2017, the book had sold 448,947 hardcover copies.

An announcement was made in February 2017 that efforts were under way to render her 1996 book It Takes a Village as a picture book. Marla Frazee, a two-time winner of the Caldecott Medal, was announced as the illustrator. Clinton had worked on it with Frazee during her 2016 presidential election campaign. The result was published on the same day of publication as What Happened. The book is aimed at preschool-aged children, although a few messages are more likely better understood by adults.

In October 2017, she was awarded an honorary doctorate from Swansea University, whose College of Law was renamed the Hillary Rodham Clinton School of Law in her honor. In October 2018, Hillary and Bill Clinton announced plans for a 13-city speaking tour in various cities in the United States and Canada between November 2018 and May 2019. Hillary was awarded an Honorary Doctorate in law (LLD) at Queen's University Belfast on October 10, 2018, after giving a speech on Northern Ireland and the impacts of Brexit at Whitla Hall, Belfast. In June 2018, Trinity College Dublin awarded her with an honorary doctorate (LLD).

A package that contained a pipe bomb was sent to Clinton's home in Washington, D.C, on October 24, 2018. It was intercepted by the Secret Service. Similar packages were sent to several other Democratic leaders and to CNN.

On March 4, 2019, Clinton announced that she would not run for president in 2020. In October 2019, Trump tweeted that Clinton should run for a third time, prompting her response of "don't tempt me". On April 28, 2020, Clinton endorsed former Vice President Joe Biden for president in the 2020 election. Clinton delivered a speech in the 2020 Democratic National Convention. On October 28, 2020, Clinton announced that she is on the Democratic slate of electors for the state of New York in the 2020 election.

Comments on President Trump

On February 27, 2017, Clinton called on President Trump to address the shooting of two Indian men by Adam Purinton. On May 2, Clinton said Trump's use of Twitter "doesn't work" when pursuing important negotiations. "Kim Jong Un ... is always interested in trying to get Americans to come to negotiate to elevate their status and their position". Negotiations with North Korea should not take place without "a broader strategic framework to try to get China, Japan, Russia, South Korea, to put the kind of pressure on the regime that will finally bring them to the negotiating table with some kind of realistic prospect for change." While delivering the commencement speech at her alma mater Wellesley College on May 26, Clinton asserted President Trump's 2018 budget proposal was "a con" for underfunding domestic programs. On June 1, when President Trump announced withdrawal of the U.S. from the Paris Agreement, Clinton tweeted that it was a "historic mistake".

On September 29, 2019, in an interview with CBS News Sunday Morning, Clinton described Trump as a "threat" to the country's standing in the world; an "illegitimate president", despite having won the election; and a "corrupt human tornado".

Chancellor of Queen's University Belfast

On January 2, 2020, it was announced that Hillary Clinton would take up the position of Chancellor at Queen's University Belfast after her husband had previously played a role in the Northern Ireland peace process and the signing of the 1998 Good Friday Agreement. Clinton became the 11th and first female chancellor of the university, filling the position that had been vacant since 2018 after the death of her predecessor, Thomas J. Moran. Commenting on taking up the position, she said that "the university is making waves internationally for its research and impact and I am proud to be an ambassador and help grow its reputation for excellence". Queen's Pro-Chancellor Stephen Prenter said that Clinton on her appointment "will be an incredible advocate for Queen's" who can act as an "inspirational role model".