Department of Homeland Security Civilian Cybersecurity Reserve Act This bill authorizes the Cybersecurity and Infrastructure Security Agency (CISA) to create a temporary Civilian Cybersecurity Reserve to address U.S. cybersecurity needs with respect to national security. Reserve members must (1) be former employees or contractors of the executive branch, former military personnel, or former state or local government employees; (2) have cybersecurity expertise; and (3) obtain any necessary security clearances. Membership in the reserve is contingent on a mutual agreement between the agency and the individual. CISA must submit an implementation plan for congressional review before taking any further action with respect to the reserve. In addition, CISA and the Government Accountability Office must evaluate and report on the reserve. The report must include recommendations that address whether the program should be made permanent, extended, or modified.