DEFINITION of 'Incumbent'. An individual that is responsible for a specific office within a corporation or government position. This person has an obligation to the position or office he/she holds.All incumbents of an organization, such as directors and officers, are listed on an incumbency certificate.This is an official or regime currently holding office or a post. For example, in politics, The incumbent governor was defeated in the elections..his term is also used in the form of an obligation.. For example, It is incumbent for the President to sign the new health care policy in order to meet the nations' current health care needs..