J.D. Vance, an author and venture capitalist whose best-selling memoir, “Hillbilly Elegy,” focused on the social and economic underpinnings of former President Donald J. Trump’s appeal to the white working class, said on Thursday that he would seek the Republican nomination for the Senate in Ohio.
Mr. Vance, 36, enters the campaign as a well-known and well-financed first-time candidate facing an open field. The Republican incumbent, Senator Rob Portman, is retiring after two terms. The race is one of a few in next year’s midterm elections that could determine which party controls the upper chamber of Congress, which is now split 50-50.
At his campaign kickoff event at a steel parts factory in Middletown, the city north of Cincinnati where he grew up, Mr. Vance made his backstory as a son of the Rust Belt central to his identity as a candidate.
He spoke at length about his upbringing, including how his “mamaw” had “kept him on the straight and narrow” as a youth, before diving into his political pitch. He staked out populist positions on issues like inequality and Big Tech and more conservative ones on matters like immigration and abortion.
“If you look at every issue in this country,” Mr. Vance said, “every issue I believe traces back to this fact: On the one hand, the elites in the ruling class in this country are robbing us blind, and on the other, if you dare complain about it, you are a bad person.”
Mr. Vance will benefit from $10 million pledged toward his campaign by the billionaire venture capitalist Peter Thiel. Mr. Thiel was an early backer of Mr. Vance who hired him and later invested in the fund Mr. Vance now runs. But in the Republican primary, Mr. Vance will face a number of candidates who are well known in Ohio G.O.P. politics, including Josh Mandel, a former state treasurer, and Jane Timken, a former chair of the state Republican Party.
Mr. Trump won Ohio twice by comfortable margins. Courting his voters — thousands of whom showed up for a rally he held last weekend outside Cleveland — will be crucial to winning a statewide Republican primary contest. Mr. Vance attended the event, Mr. Trump’s first since his supporters stormed the Capitol on Jan. 6, but he did not speak there.
After the 2016 publication of “Hillbilly Elegy,” Mr. Vance leveraged his fame into a part-time career as a fixture on the speaking circuit and as a media commentator. Lately, he has staked out a position among the more populist voices in his party who are targeting social media companies, China and the left wing of the Democratic Party.
The arc of Mr. Vance’s short time as a quasi-political figure has followed the prevailing mood among Republican office holders since Mr. Trump won in 2016. At first, he was deeply critical of the former president, calling him “noxious” and saying he worried Mr. Trump was “leading the white working class to a very dark place.”
But today Mr. Vance is a prolific tweeter and occasional Fox News guest who has adopted Trumpian culture war language, denouncing “wokeness” and calling for more restrictive immigration policies.
His Republican opponents have already started dusting off his old anti-Trump statements as a way of suggesting that he is insincere and has lost touch with working-class Ohio.
Mr. Vance today is in a much different place than the young man he describes in “Hillbilly Elegy,” who struggled to overcome adversity; a mother who had a long history with substance abuse; family members who could not control their anger; and opioid-addicted friends and neighbors.
He served in the Marines, graduated from Yale Law School and joined Mr. Thiel’s venture capital firm. “Hillbilly Elegy” was made into a movie directed by Ron Howard that was released last year.