WASHINGTON — Tom Daschle formally began the incoming administration’s arduous quest to overhaul the nation’s health care system on Thursday, telling former Senate colleagues that the task had become more urgent because many people were losing health insurance, along with their jobs, in the recession.

Members of both parties offered a friendly welcome to Mr. Daschle, the man chosen by President-elect Barack Obama to be secretary of health and human services, in charge of a department with 65,000 employees and a budget of more than $700 billion a year.

The hearing was the first of many to be held for members of the team being assembled by Mr. Obama. The questions and answers touched only briefly on the economic and fiscal crisis that will test the new administration.

Mr. Daschle spoke with passion about the hardship he had witnessed among people without insurance, who he said faced “total economic destruction” if they became ill. “The stories of personal bankruptcy are the ones that come back to me so frequently,” he said.

He predicted that “as we face a harsh and deep recession, the problem of the uninsured is likely to grow.” Mr. Obama has promised to offer affordable coverage to the more than 45 million people who are uninsured.

Having represented South Dakota in the House for 8 years and in the Senate for 18, Mr. Daschle understands the ways of Washington. He graciously answered questions from senators, echoed their concerns and fluently discussed fine points of health policy without consulting notes or briefing books.

Senator Edward M. Kennedy, Democrat of Massachusetts, presided over the hearing as chairman of the Committee on Health, Education, Labor and Pensions. Mr. Kennedy, who is battling brain cancer, hailed Mr. Daschle as the man who could achieve a goal that Democrats have pursued for decades.

“Reform is urgently needed,” Mr. Kennedy said, “and Tom Daschle is just the person for the job.”

Mr. Daschle will have another hearing, before the Finance Committee, where he is likely to face tougher questions about Medicare, Medicaid and other entitlement programs. But Mr. Daschle appears likely to win confirmation soon after Mr. Obama takes office on Jan. 20.

In response to questions, Mr. Daschle told Republicans that he would work with them on overhauling the health care system.

“I really want to work in a collaborative way,” said Mr. Daschle, who was introduced and endorsed by Bob Dole, the former Senate Republican leader and onetime presidential candidate.

Mr. Daschle said the Obama administration would not try to rush health care legislation through Congress under expedited budget procedures, which would limit the opportunity for debate and amendments.

“I’m determined to work with each of you and use the regular order to produce the best product we can,” Mr. Daschle said.

The hearing did not indicate how far and how fast Mr. Obama would go in efforts to remake the health care system.

“When health care reform collapsed in 1994,” Mr. Daschle said, “I remember all the criticisms people had after the fact. They said it took too long, they said the process was too opaque, they said the plan was too hard to understand and they said the changes felt too dramatic.

“These are good arguments for undertaking reform in a way that is aggressive, open and responsive to Americans’ concerns,” he said. “They are not good arguments for ignoring the problem.”

Elsewhere on Capitol, Hill, the Senate Republican leader, Mitch McConnell of Kentucky, said the nation’s economic problems would “inhibit our ability” to expand federal health programs. Medicare, like Social Security, already faces enormous “unfunded liabilities,” he said.

On other issues, Mr. Daschle said he would reduce the influence of politics at federal science agencies, seek more money for community health centers, speed the approval of low-cost generic versions of prescription drugs and try to increase Medicare payments to family doctors and other primary care physicians.

He also said he would increase federal support for rural health care providers, encourage greater use of health information technology and place more emphasis on the prevention of disease, rather than the treatment of it.

Mr. Daschle was not asked, and did not say, how he would pay for the new initiatives.

His testimony came as projections from the Congressional Budget Office showed that the budget deficit would reach a record $1.2 trillion this year, without counting the costs of legislation to revive the economy.

Mr. Daschle said he would welcome changes in the way Medicare paid doctors. Medicare now uses a fee schedule, which pays a separate fee for each service.

Instead of this arrangement, Mr. Daschle said, Medicare should pay for “healthy outcomes” and “episodes of care,” which could include the work of doctors and hospitals.