WASHINGTON — Antony J. Blinken, a defender of global alliances and President-elect Joseph R. Biden Jr.’s closest foreign policy adviser, is expected to be nominated for secretary of state, a job in which he will try to coalesce skeptical international partners into a new competition with China, according to people close to the process.

Mr. Blinken, 58, a former deputy secretary of state under President Barack Obama, began his career at the State Department during the Clinton administration. His extensive foreign policy credentials are expected to help calm American diplomats and global leaders alike after four years of the Trump administration’s ricocheting strategies and nationalist swaggering.

Mr. Biden is also expected to name another close aide, Jake Sullivan, as national security adviser, according to a person familiar with the process. Mr. Sullivan, 43, succeeded Mr. Blinken as Vice President Biden’s national security adviser, and served as the head of policy planning at the State Department under Hillary Clinton, becoming her closest strategic adviser.