The agency now known as the Federal Bureau of Investigation was founded in 1908 when Attorney General Charles J. Bonaparte appointed an unnamed force of Special Agents to be the investigative force of DOJ. Prior to that time, DOJ borrowed Agents from the U.S. Secret Service to investigate violations of federal criminal laws within its jurisdiction.

By order of Attorney General George W. Wickersham, the Special Agent force was named the Bureau of Investigation in 1909. Following a series of changes in name, the Federal Bureau of Investigation officially received its present title in 1935.
During the early period of the FBIs history, its Agents investigated violations of some of the comparatively few existing federal criminal violations, such as bankruptcy frauds, antitrust crime, and neutrality violations. During World War I, the Bureau was given responsibility for espionage, sabotage, sedition, and draft violations. Passage of the National Motor Vehicle Theft Act in 1919 further broadened the Bureaus jurisdiction.
The Gangster Era began after passage of Prohibition in 1920. Criminals engaged in kidnapping and bank robbery, which were not federal crimes at that time. This changed in 1932 with the passage of a federal kidnapping statute. In 1934, numerous other federal criminal statutes were passed, and Congress gave Special Agents the authority to make arrests and to carry firearms.
The FBIs size and jurisdiction during World War II increased greatly and included intelligence matters in South America. With the end of that war and the advent of the Atomic Age, the FBI began conducting background security investigations for the White House and other government agencies, as well as probes into internal security matters for the Executive Branch.
Civil rights and organized crime became major concerns of the FBI in the 1960s, as did counterterrorism, financial crime, drugs, and violent crimes, during the 1970s and 1980s.
In additional to its five priority programs, the FBI also concentrates significant investigative resources into applicant and civil rights matters.

Federal Bureau of Investigation and Prior Names

Designated as Date
No specific name assigned; referred to as Special Agent Force July 26, 1908
Bureau of Investigation March 16, 1909
United States Bureau Of Investigation July 1, 1932
Division of Investigation (The Division also inculded the Bureau of Prohibition.) August 10, 1933
Federal Bureau of Investigation July 1, 1935

Leaders of the Federal Bureau of Investigation and Predecessor Agencies

Leader Date Assumed Office
Stanley W. Finch
(After March 16, 1909, when AG Wickersham erected the BOI, Finch took the title Chief of the BOI.)
July 26, 1908
Alexander Bruce Bielaski April 30, 1912
William E. Allen (Acting) February 10, 1919
William J. Flynn July 1, 1919
William J. Burns August 22, 1921
J. Edgar Hoover (Mr. Hoover was designated Acting Director on May 10, and permanent Director on December 10, 1924.) May 10, 1924
L. Patrick Gray (Acting) May 3, 1972
William D. Ruckelshaus (Acting) April 27, 1973
Clarence M. Kelley July 9, 1973
William H. Webster Febraury 23, 1978
John E. Otto (Acting) May 26, 1987
William S. Sessions November 2, 1987
Floyd I. Clarke (Acting) July 19, 1993
Louis J. Freeh September 1, 1993