"I'm focused on serving the folks in the 4th District that I get the privilege to represent," Jordan told WLIO-TV.
With Jordan out of the race, several other Ohio Republicans are being mentioned as potential Republican primary candidates for Portman's seat, including Lt. Gov. Jon Husted, Reps. Steve Stivers and Pat Tiberi.
Ohio has long been considered a battleground state. Former President Donald Trump carried the state in both 2016 and 2020 and Jordan has been one of his staunchest defenders in Congress. He was awarded the presidential medal of freedom in the final days of Trump's term.
Jordan, 56, has also been a vocal critic of House lawmakers who voted quickly to impeach Trump this month for inciting an insurrection at the U.S. Capitol on Jan. 6. He said it was an example of Democrats' "obsession."
Trump won 67% of the vote in Jordan's district last November.