The Senate voted on Tuesday to confirm Frank Bisignano as commissioner of the Social Security Administration, which has been thrown into turmoil after a three-month stretch steered largely by Elon Musk’s unofficial Department of Government Efficiency.

President Trump’s nominee was confirmed by a vote of 53 to 47, which had been expected and was split along party lines.

Mr. Bisignano, a former Wall Street executive, will take the helm at a critical juncture. A series of recent changes led by DOGE, from deep job cuts to exploiting sensitive databases, have rattled current and former employees, former commissioners of both parties, beneficiaries and their advocates. They have been alarmed by the fast and seemingly haphazard moves, as well as the departure from established protocols that protect beneficiaries’ privacy and ensure they continue to receive payments.

The question is whether Mr. Bisignano, 65, the former chief of the payments giant Fiserv, will steady the agency, which delivers retirement, disability and survivor payments to 73 million Americans every month.

Senator Mike Crapo, a Republican from Idaho who leads the Finance Committee, urged his colleagues last week to vote in favor of Mr. Bisignano, emphasizing his decades of experience leading large financial institutions, and noting his commitment to improving customer service at the agency.

But Democratic lawmakers remained unconvinced, and they continued to raise many of the same concerns they grilled Mr. Bisignano about during his three-hour Senate confirmation hearing in late March: Would he give in to calls by DOGE that could further hobble the program, or will he act independently in the best interest of the agency and its beneficiaries?