Senator Josh Hawley, the Missouri Republican, said on Monday that he had decided to support the nomination of Dr. Mehmet Oz to lead Medicare and Medicaid because Dr. Oz told him that he would no longer support transgender care for minors and was “unequivocally pro-life.”

The Senate is expected to vote on Dr. Oz’s nomination to become administrator of the Centers for Medicare and Medicaid Services sometime this month.

Mr. Hawley was vocal about withholding his support for Dr. Oz, a cardiothoracic surgeon who became a daytime TV celebrity, over concerns about his previous positions on transgender care and certain state abortion laws. Dr. Oz featured segments on the television show about transgender care and had also previously raised possible objections to proposed state legislation that would prohibit abortion based on fetal heartbeats.

In his responses to Mr. Hawley’s written questions, Dr. Oz assured the senator that he “disavows his previous support for trans surgeries & drugs for minor children,” Mr. Hawley posted on X, the social media site. He added that he “also walks back past criticism of state pro-life laws.” Dr. Oz said he would also “work to end funding for abortion providers,” Mr. Hawley said.

Mr. Hawley’s opposition could have jeopardized Dr. Oz’s confirmation, given that Democrats seemed likely to vote against him along party lines. C.M.S. is a $1.5 trillion agency responsible for providing health care coverage to nearly half of Americans.

Last month, Mr. Hawley successfully forced the ouster of a new chief counsel, Hilary Perkins, at the Food and Drug Administration over her work as a Biden administration lawyer who argued in defense of the availability of the abortion pill. She is an anti-abortion conservative.

A spokesman for Dr. Oz did not return a request for comment.