When Joseph R. Biden Jr. and Kamala Harris take the oath of office on Wednesday, they will instantly make history, as Ms. Harris becomes the first woman to hold the nation’s second highest office. Forced to hold their celebration amid tragedy, as the nation remains mired in the coronavirus pandemic and faces threats of right-wing violence, they will seek to cast their inauguration as a hopeful moment for the country.

In so many ways, this is a moment Mr. Biden and Ms. Harris have prepared for their entire careers. They each entered politics as young adults, staking out positions as moderate Democrats and clearly harboring ambition for higher office.

As a young man, Mr. Biden sat out the Vietnam-era activism that animated so many others in his generation, an early prelude to his lifelong image as a family man not particularly interested in courting controversy. Mr. Biden’s first two presidential runs, two decades apart, fizzled out. But after spending eight years as vice president, Mr. Biden was able to cast his third presidential bid as a way of cementing — and in many ways, restoring — President Barack Obama’s legacy after a tumultuous term under President Donald J. Trump.

Ms. Harris, the daughter of immigrants from Jamaica and India, and speaks frequently of being pushed in a stroller during civil rights demonstrations in California’s Bay Area. As a child, she traveled to see her mother’s family in India, trips that shaped her for the rest of her life. At the same time, Ms. Harris’s mother raised her to see herself as a Black woman, as she knew the world would view her daughter. Ms. Harris chose to attend college at Howard University, where she honed her own views about power.

Here is a look back at articles by The New York Times that illustrate the paths that led Mr. Biden and Ms. Harris to their roles as president and vice president.

Joe Biden’s Non-Radical 1960s

Mr. Trump often criticized Mr. Biden as a tool of leftist agitators. Friends say that has never much been his way, even as a young man surrounded by protest. As he put it in a campaign speech: “Do I look like a radical socialist with a soft spot for rioters?” Read the complete article here.

How Kamala Harris’s Family in India Helped Shape Her Values

Ms. Harris gained part of her foundation from her mother’s side of the family, which defied stereotypes in India and promoted equality for women. Read the complete article here.

Biden’s First Run for President Was a Calamity. Some Missteps Still Resonate.

In his 1988 campaign, Mr. Biden was prone to embellishment. Hints of that linger today. But unlike then, his message to voters during his final bid was clear: He’s a stabilizing statesman in a tumultuous time. Read the complete article here.

What Kamala Harris Learned About Power at Howard

As a college student, Ms. Harris wanted to have an impact. The method she landed on — pushing for change by working inside institutions — set her on the path to the vice presidency. Read the complete article here.

Obama and Biden’s Relationship Looks Rosy. It Wasn’t Always That Simple.

Their partnership is the stuff of buddy-movie lore, but those who saw it up close described a more difficult, complicated dynamic. Read the complete article here.

What Kamala Harris Believes

During the 2020 Democratic presidential primary, Ms. Harris found herself in a potent but unpredictable position: Voters thrilled to her as a messenger, yet the content of her message remained a work in progress. Read the complete article here.