"Like to prank" is the first thing most friends and former assistants think about when asked about Jill, the wife who is attached to Joe Biden.

Jill Biden once sneaked into an assistant's birthday party, dressed like a waitress and suddenly came to the party to wish the owner of the party.

"She knows very well that it's important to bring a smile, a little fun, and comfort in big moments," said Courtney O'Donnell, Joe Biden's communications director when he was younger.

Jill, 69, married Joe Biden in 1977, more than four years after his first wife and daughter died in a car accident.

When Joe Biden was elected senator and moved from Delaware to Washington, Jill became a teacher.

According to former colleagues, on the career path of Joe Biden, Jill acted as one of the most vocal political advisers.

After Joe Biden became the presidential candidate representing the Democratic Party this year, Jill has contributed a great voice in the selection process of the vice presidential candidate, appearing with them at various events.

"The final decisions are still with Joe," she added.

People close to Jill Biden say she feels a bit embarrassed to be called one of her husband's most important "counselors", claiming her relationship with her husband is much deeper than her role "

"He has loads of political advisers. Jill is not like that," said Cathy Russell, Jill's chief of staff under the Obama administration, now Joe Biden's campaign vice president.

Jill Biden is actually one of her husband's closest confidants, especially nowadays, as they spend most of their time indoors in Wilmington do Covid-19.

"At night, they always try to sit together, summarize everything for the day and talk about everything," Russell said.

Identifying himself as an introvert, Jill was initially not interested in becoming the wife of a politician.

"Just thinking about it made me feel sickly nervous," she said.

But with eight years as the lady of the US vice president, Jill was forced to get used to the speeches.

She has appeared in online events held in 17 cities since May.

Last month, Jill appeared at almost every husband's campaign, sharing emotionally and fluently about her husband's development plans for different constituencies.

Jill is also the fiercest defender of her husband, the quality that she herself identified in her memoir.

But Jill's dislike of being called her husband's "mentor" shows that she is an independent person who wants to make a career and a mark of her own.

"She also has a life of her own, raising children, teaching," said Russell.

Jill Biden continued to teach at a community college when her husband was vice president, against the advice of many advisers at the time.

"The teacher is not my profession, but who I am," she wrote in her memoirs, also delighting in describing "getting into a prom dress and wearing high heels" in a school bathroom to

Aides said Jill would continue to fight the issues she had been concerned with as the vice president if she returned to the White House as first lady.

Besides, Jill once said she still plans to continue to teach if she becomes the first lady of America.

According to Mary Doody, a longtime friend and colleague at Jill's university, the class gives her a private space, separate from her political life.

"When you go to class, you spend time with students for an hour and a half, two hours or whatever the time, then it's only you with them and you have to work hard to build this relationship.