WASHINGTON — President Obama nominated Gayle Smith, a senior White House official, on Thursday to be the next administrator of the United States Agency for International Development, administration officials said.

If confirmed by the Senate, Ms. Smith, a longtime development and Africa specialist in the Clinton and Obama administrations, would succeed Dr. Rajiv Shah, who left the agency in February after five years on the job.

Ms. Smith, 59, who is well-known in Washington development circles, would be responsible for leading the government’s response to humanitarian disasters like the earthquake in Nepal, the refugee crisis in Syria and the receding Ebola epidemic in West Africa, as well as managing the agency’s $20 billion budget.

She would also have to figure out a way to duplicate her predecessor’s skillful managing of congressional Republicans. Dr. Shah was widely credited with successfully defending the agency’s budget at a time of belt-tightening and intense partisanship. He was also known for innovative programs that sought to tackle global health and development challenges in unusual ways.