Jared Kushner ruled out on Tuesday a return to the White House if his father-in-law, former President Donald J. Trump, were elected in November.

Mr. Kushner, when asked at an Axios summit in Miami whether he would be open to joining a second Trump administration, said he was focused on his private equity firm, Affinity Partners.

“I’ve been very clear that my desire at this phase of my life is to focus on my firm,” he said. “I’ve really enjoyed the opportunity as a family to be out of the spotlight.”

Mr. Kushner, who is married to Mr. Trump’s daughter Ivanka, was a senior adviser to Mr. Trump during his father-in-law’s term.

He was pressed by Dan Primack, an Axios business editor, on how he would respond if Mr. Trump called on him to return. “You say, ‘Thanks, but I’m good?’” Mr. Primack said. Mr. Kushner replied: “Yes.”

He added that Mr. Trump had assembled a deep bench of trusted confidants to guide him if voters returned him to the White House, and described being an adviser as a “24-7 high-stakes job.”

“The last time, it really was a family campaign,” he said.