From Wikipedia, the free encyclopedia. A Contracting Officer (CO or KO) is a person who can bind the Federal Government of the United States to a contract that is greater than the Micro-Purchase threshold. This is limited to the scope of authority delegated to the Contracting Officer by the head of the agency. A Contracting Officer enters into, administers, or terminates contracts and makes related determinations and findings, and is appointed by a (SF) 1402, Certificate of Appointment.