Soon: Ms. Rollins served as president of the conservative Texas Public Policy Foundation, an influential nonprofit that has worked to push public funding to private schools, increase the role of Christianity in civic life and heavily promote fossil fuels.

Then: Under the Biden administration, the department, led by Tom Vilsack, has prompted the largest-ever permanent increase in food stamp benefits, strengthened antitrust rules in the meatpacking sector and invested billions in regenerative or so-called climate-smart farming practices.