Here are some things to know about Vance, a 39-year-old Republican now in his first term in the Senate:

Vance rose to prominence with memoir 'Hillbilly Elegy'

Vance was born and raised in Middletown, Ohio. He joined the Marines and served in Iraq, and later earned degrees from Ohio State University and Yale Law School. He also worked as a venture capitalist in Silicon Valley.

Vance made a name for himself with his memoir, the 2016 bestseller "Hillbilly Elegy," which was published as Trump was first running for president. The book earned Vance a reputation as someone who could help explain the maverick New York businessman's appeal in middle America, and especially among the working class, rural white voters who helped Trump win the presidency.

"Hillbilly Elegy" also introduced Vance to the Trump family. Donald Trump Jr. loved the book and knew of Vance when he went to launch his political career. The two hit it off and have remained friends.

He was first elected to public office in 2022

After Donald Trump won the 2016 election, Vance returned to his native Ohio and set up an anti-opioid charity. He also took to the lecture circuit and was a favored guest at Republican Lincoln Day dinners where his personal story -- including the hardship Vance endured because of his mother's drug addiction -- resonated.

Vance's appearances were opportunities to sell his ideas for fixing the country and helped lay the groundwork for entering politics in 2021, when he sought the Senate seat vacated by Republican Rob Portman, who retired.

Trump endorsed Vance. Vance went on to win a crowded Republican primary and the general election.

Vance went from never-Trumper to fierce ally

Vance was a "never Trump" Republican in 2016. He called Trump "dangerous" and "unfit" for office. Vance, whose wife, lawyer Usha Chilukuri Vance, is Indian-American and the mother of their three children, also criticized Trump's racist rhetoric, saying he could be "America's Hitler."

But by the time Vance met Trump in 2021, he had reversed his opinion, citing Trump's accomplishments as president. Both men downplayed Vance's past scathing criticism.

Once elected, Vance became a fierce Trump ally on Capitol Hill, unceasingly defending Trump's policies and behavior.

He is a leading conservative voice

Kevin Roberts, president of the conservative Heritage Foundation, called Vance a leading voice for the conservative movement, on key issues including a shift away from interventionist foreign policy, free market economics and "American culture writ large."

Democrats call him an extremist, citing provocative positions Vance has taken but sometimes later amended. Vance signaled support for a national 15-week abortion ban during his Senate run, for instance, then softened that stance once Ohio voters overwhelmingly backed a 2023 abortion rights amendment.

On the 2020 election, he said he wouldn't have certified the results immediately if he had been vice president and that Trump had "a very legitimate grievance." He has put conditions on honoring the results of the 2024 election that echo Trump's. A litany of government and outside investigations have not found any election fraud that could have swung the outcome of Trump's 2020 loss to Democratic President Joe Biden.

In the Senate, Vance sometimes embraces bipartisanship. He and Democratic Ohio Sen. Sherrod Brown co-sponsored a railway safety bill following a fiery train derailment in the Ohio village of East Palestine. He's sponsored legislation extending and increasing funding for Great Lakes restoration, and supported bipartisan legislation boosting workers and families.

Vance brings strengths at debating, fundraising

People familiar with the vice presidential vetting process said Vance would bring to the GOP ticket debating skills, fundraising prowess and the ability to articulate Trump's vision.

Charlie Kirk, founder of the conservative activist group Turning Point USA, said Vance compellingly articulates the America First world view and could help Trump in states he closely lost in 2020, such as Michigan and Wisconsin, that share Ohio's values, demographics and economy.