Jill Biden took centre stage in her husband Joe’s campaign to be US president when she addressed the Democratic convention on Tuesday.
Ms Biden is a teacher with doctorate in education, a home-maker who raised their three children, and a valuable political adviser to husband Joe.
The two married in 1977, a few years after his first wife and his young daughter died in a car accident.
Ms Biden, 69, was wary of his 1988 presidential campaign but pushed him to run again in 2008, according to her memoir.
After Mr Biden became the nominee this year, she played a prominent role in auditioning many of vice presidential candidates.
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Ms Biden recently acknowledged that she and her husband “talked about the different woman candidates".
“But it’s gotta be Joe’s decision,” she told CBS TV.
Those who know Ms Biden best say her relationship with her husband is deep and nuanced.
“He’s got plenty of political advisers. That’s not what she is,” said Cathy Russell, Ms Biden’s chief of staff during the Obama administration and now a vice chair on the campaign.
“She is his spouse, and she loves him and she talks to him about all sorts of things.
"But she has a unique role, and it’s not being a political adviser. That’s not her thing.”
A self-described introvert, Ms Biden was initially a reluctant political wife.
In her memoir, she writes of giving her first political speech and having no desire to “give any speeches, any time, anywhere.
"Just the thought of doing so made me so nervous I felt sick.”
But after eight years as the vice president’s wife and giving speeches and appearing at events after her husband left office, Ms Biden is now one of his most prominent surrogates.
She has appeared in online events in more than 17 cities since May, and is one of the campaign’s primary workers to Latino voters.
Ms Biden continued to teach at a community college while her husband was vice president, against the advice of aides at the time.
“Being a teacher is not what I do but who I am,” she wrote in her memoir.
She described “scrambling into a cocktail dress and heels” in the bathroom at her school to make it to a White House reception, or grading papers on Air Force Two with relish.
Ms Biden has said she plans to continue teaching if she becomes first lady.
