MILWAUKEE, the United States - J.D. Vance, a senator from the US state of Ohio and author of the bestselling memoir "Hillbilly Elegy", on Wednesday night accepted the nomination for vice president at the ongoing Republican National Convention in Milwaukee, Wisconsin.

Introducing himself to the nation as Donald Trump's vice-presidential pick, Vance used his speech at the convention to recount his tough upbringing and argue that the Republican Party is most attuned to the difficulties faced by struggling Americans, especially the overlooked working class.

"To the people of Middletown, Ohio, and all the forgotten communities in Michigan, Wisconsin, Pennsylvania and Ohio, and every corner of our nation, I promise you this," Vance said. "I will be a vice president who never forgets where he came from."

Vance, 39, had a tumultuous childhood and was raised by his grandparents in impoverished Rust Belt Ohio. He joined the Marines after graduating from high school and later attended Ohio State University and Yale Law School.

He was once a fierce critic of Trump but shifted his opinion after meeting Trump in 2021, becoming a close ally and a staunch defender. He was elected to the US Senate in 2022 with Trump's endorsement.

Wednesday marks the third day of the Republican National Convention. Former House Speaker Newt Gingrich, Former Director of the US Office of Trade and Manufacturing Policy Peter Navarro, and Texas Governor Greg Abbott were among a long list of speakers.

On Tuesday, Trump's former rivals and critics, including former US Ambassador to the United Nations Nikki Haley, Florida Governor Ron DeSantis, and Senator Marco Rubio, took the stage to make speeches, highlighting the party's unity.

Trump, who just recently survived an attempted assassination, is expected to accept the Republican nomination for president on Thursday and will make a keynote speech.