JD Vance will step down from his Senate seat at midnight Thursday, just days before being sworn in as US vice president, his spokesperson confirmed.
Vance must resign from the Senate before his inauguration on Jan. 20.
Ohio's Republican Governor Mike DeWine will appoint someone to fill the vacant seat.
"As I prepare to assume my duties as Vice President of the United States, I would like to express that it has been a tremendous honor and privilege to serve the people of Ohio in the Senate over the past two years," Vance wrote in his resignation letter to DeWine, effective Jan. 10, according to CNN.
Following Vance's resignation, DeWine is expected to announce his appointee.
"I was elected to this office, I promised to never forget where I came from, and I've made sure to live by that promise every single day," Vance said separately, addressing his Ohio district.
"The American people have granted President Trump an undeniable mandate to put America first, both at home and abroad," he added.
"Over the next four years, I will do all that I can to help President Trump enact his agenda. Together, we will make America stronger, safer, and more prosperous than ever before," he said.
DeWine's appointee will serve until 2026 and must run in a special election to complete the remaining two years of Vance's term.
After that, the individual will need to campaign in 2028 for a full six-year term.
In an interview with CNN, DeWine said he's seeking a replacement who will be "a worker in the US Senate," drawing on his own experience as a two-term senator.
"I think I have a pretty good idea of what it takes to be successful. I want someone who understands Ohio, who has a deep knowledge of our state, a strong advocate there," DeWine said, adding that the appointee must be "willing" to run for a full term in two years and capable of winning both the primary and general elections.
