WASHINGTON—Late Sunday, a group representing thousands of FBI agents told its members it was optimistic about the agency’s future, in part because its new director, Kash Patel, had assured the group he would choose a deputy from among their ranks.

The appointment of Bongino, a former Secret Service agent and NYPD officer turned conservative radio host, puts a second Trump ally at the top of the agency.

Bongino, a former Secret Service agent, has been criticized for spreading several conspiracy theories as a talk show host.