FCC Chairman Julius Genachowski will be the defense commissioner, according to the commission.
The commission designates one commissioner to head up homeland security, national security and emergency preparedness. That makes him the point person with the Department of Homeland Security and makes him responsible for emergency preparedness programs.
The chairman has already launched a review of the FCC's emergency preparedness procedures.
Fellow Democrat Michael Copps will be alternate defense commissioner for a one-year term.