Deputy Secretaries and Under Secretaries

Early cabinet departments were small enough for a secretary and a chief clerk to manage, but as they grew, Congress added assistant secretaries in the nineteenth century and under secretaries in the twentieth, beginning with the Under Secretary of State in 1919. The title deputy secretary appeared with the Deputy Secretary of Defense in 1949 and spread to most departments by the 1970s and 1980s. These positions are created by statute, filled by presidential nomination with Senate confirmation, and listed in the Plum Book, published after each presidential election.

The deputy secretary is the second-ranking official in a department, typically acting as its chief operating officer, managing budgets and personnel, and representing the department in interagency meetings, and by law the deputy usually becomes acting secretary when the top job is vacant. Under secretaries lead major parts of a department, such as the Under Secretary of State for Political Affairs, the Under Secretary of Defense for Policy, or the Under Secretary of Agriculture for Food Safety, and assistant secretaries below them oversee specific bureaus and offices. Together they form the political leadership layer that sits above the career civil service.

The federal government has about 1,300 positions requiring Senate confirmation, and many deputy and under secretary posts remain vacant for long stretches as nominations move slowly, leaving acting officials in charge under the Federal Vacancies Reform Act. In September 2025 the Senate changed its rules by majority vote to allow groups of sub-cabinet nominees to be confirmed together in a single vote. Supporters said the change ended partisan delays that left agencies without leaders, while critics said it weakened the Senate's scrutiny of individual nominees.