DHS Joint Requirements Council Act of 2018 This bill amends the Homeland Security Act of 2002 to authorize the Department of Homeland Security (DHS) to establish leadership councils to ensure coordination and improve programs and activities of the department. DHS must establish a Joint Requirements Council within the department to: identify, assess, and validate joint requirements to meet mission needs; ensure that appropriate efficiencies are made among life-cycle cost, schedule, performance, and procurement quantity objectives in the establishment and approval of joint requirements; and make prioritized capability recommendations for the joint requirements. A "joint requirement" is a condition or capability of multiple operating components of DHS that is required to be met or possessed by a system, product, service, result, or component to satisfy a contract, standard, specification, or other formally imposed document.