Jill Biden once said that she knew marrying Joe Biden — then a senator from Delaware — would mean "a life in the spotlight that I had never wanted”.

On Monday night, now very accustomed to that spotlight, the first lady stood before the Democratic National Convention to do her part to highlight her husband's 50 years of public service as his presidency begins to draw to a close.

Her words marked the beginning of an end for her, too.

Before the president walked across the stage at the United Centre to deliver the keynote speech on the convention's opening night, the first lady used her address to speak to his character and reiterate her support for Vice President Kamala Harris.

"Joe and I have been together for almost 50 years, and still there are moments when I fall in love with him all over again," she said. Among them, she said, was watching him “dig deep into his soul and decide to no longer seek reelection and endorse Kamala Harris”.

Jill Biden urged Americans to unite with “faith in each other, hope for a brighter future, and love for our country".

President Biden endorsed Harris shortly after he dropped out of the presidential race in July, and she has succeeded him as the Democratic Party's nominee.

In the weeks before Biden decided to leave the race, the first lady had declared that she was “all in” on her husband's reelection plan, even as Democrats began calling on him to drop out following his disastrous performance in a debate against Republican Donald Trump on June 27.

Biden himself had brushed aside those calls, repeatedly insisting that he was staying in the race. His wife, one of his fiercest supporters and defenders, backed him up.

“For all the talk out there about this race, Joe has made it clear that he's all in,” the first lady told a crowd in Wilmington, North Carolina, on July 8. “That's the decision that he's made, and just as he has always supported my career, I am all in, too."

Biden pulled the plug on his campaign on July 21.

The president was introduced by Ashley Biden, his only living daughter, who humanized her father as “the OG girl dad” in a deeply personal speech.

She described “this extraordinary journey of being Joe Biden's daughter,” remembering a time he made a special trip home during a busy period in Washington to be with her when she blew out candles on her eighth birthday, then got back on the train to return to the nation's capital. And she lionised his public service, calling him “one of the most consequential leaders ever in history”.

After Joe Biden took the stage to extended applause and chants of “thank you Joe,” he proudly proclaimed, “that was my daughter!”

The first night of the four-day Democratic convention was rearranged after Biden bowed out. It honoured his record of public service, including six terms as a US senator from Delaware, eight years as vice president and one four-year term as president.

Jill Biden was with her husband through it all and now both are figuring out what they want to accomplish in the time they have left in the White House.

During the remaining months of the administration, which ends in mid-January, aides say Jill Biden will continue to work on her favoured causes: supporting military families through her Joining Forces initiative, reducing cancer's toll through the Biden Cancer Moonshot, advancing research into women's health under an effort launched in November 2023, and increasing opportunities for education.

She is also expected to campaign for Harris this fall.

The first lady charted a new path for presidential spouses when she became the first to hold a paying job outside the White House. She is an English and writing professor at Northern Virginia Community College, where she has taught since 2009, and has been working on her lesson plans for the coming fall semester, aides said.

As first lady, Jill Biden travelled to over 40 states, over 200 towns and cities, and 19 countries, most recently leading a delegation to support Team USA at the Olympic Games in France.

She spent the first year of the administration travelling around the United States encouraging people to get vaccinated against COVID-19.

In 2022, she travelled to Ukraine after Russia's military invasion to show US support for Ukrainians.