The Office of Commissioner of Internal Revenue was created by Congress on July 1, 1862. The Bureau of Internal Revenue was created to collect taxes used to finance the Civil War. The income tax was abolished after 10 years but the agency remained to collect other revenues. The income tax was reinstated in 1913. See History of the IRS for more information.
Commissioners are nominated by the president and confirmed by the Senate. The IRS Commissioner and the IRS Chief Counsel are the only appointees within the agency. All other employees are career civil servants. Since the IRS Restructuring and Reform Act of 1998, commissioners have been appointed to a five-year term.