WASHINGTON — The Senate confirmed billionaire investor Scott Bessent on Monday to serve as President Trump’s treasury secretary, giving him the delicate balancing act of cutting taxes and curbing deficits while putting forward a plan on tariffs that doesn’t jeopardize growth.

He was confirmed on a 68-to-29 vote, with 16 Democrats voting in favor of making him the nation’s 79th treasury secretary.

The South Carolina resident will be the first openly gay individual in the role, a historic first as Mr. Trump seeks novel ways to implement a policy agenda driven by both billionaire business leaders with concerns over regulations and a populist base that wants government leaders to fight for them.

Mr. Bessent, a past supporter of Democrats who once worked for George Soros, has become an enthusiastic supporter of Mr. Trump.

The new Treasury chief has said America faces economic calamity if Congress does not renew key provisions of Mr. Trump’s Tax Cuts and Jobs Act that are set to expire December 31, 2025.

Negotiating the extension of those tax cuts will be one of his major responsibilities even as he has also pushed for 3 percent annual growth, significant trims to deficits and increasing domestic oil production by 3 million barrels a day.

After Mr. Bessent was confirmed, Senator Crapo of Idaho, chairman of the Senate Finance Committee, said approving Mr. Bessent was “one of the easiest votes we could ever take.”

However, he faced pushback from Democrats on unpaid tax liabilities.

Democrats say Mr. Bessent has engaged in tax avoidance by failing to pay nearly $1 million in Medicare taxes related to his limited partnership in his hedge fund. Mr. Bessent, meanwhile, takes issue with his tax liability to the IRS and is in litigation over the tax bill. He committed during his confirmation hearing that he would pay the tax bill if a court rules against him.

Other Democrats have voiced support for Mr. Bessent, including Senator Coons, of Delaware.

“While I disagree with many of his policy positions, particularly his support for extending tax cuts for the wealthy and President Trump’s tariff threats, I hope that he will focus the Treasury Department on bringing down costs for middle-class Americans,” Mr. Coons said in a statement, adding that he supports Mr. Bessent’s commitment to continue American investment in international financial institutions such as the World Bank and the International Monetary Fund.

Mr. Trump took his time before settling on Mr. Bessent as his nominee. He also mulled over billionaire investor John Paulson and Howard Lutnick, whom Trump tapped for commerce secretary.

The treasury secretary is responsible for serving as the president’s fiscal policy adviser and managing the public debt. He is also a member of the president’s National Economic Council.

Among his responsibilities will be investigating the feasibility of creating an External Revenue Service to collect tariff revenue from other nations. Mr. Trump announced the creation of the agency — which requires an act of Congress— on Truth Social earlier this month.

Tariffs have become a benchmark of Mr. Trump’s economic agenda. He has threatened a potential 25 percent levy on all goods from allies like Canada and Mexico and 60 percent on goods from Communist China.

In addition, Mr. Bessent faces a mounting and record American debt burden. Before leaving office this month, Secretary Yellen warned congressional leaders that Treasury would start taking “extraordinary measures,” or special accounting maneuvers intended to prevent the nation from hitting the debt ceiling. And on Thursday, Treasury deployed such measures.

Associated Press