The mission of the Department of Justice is to enforce the law and defend the interests of the United States according to the law; to ensure public safety against threats foreign and domestic; to provide federal leadership in preventing and controlling crime; to seek just punishment for those guilty of unlawful behavior; and to ensure fair and impartial administration of justice for all Americans.

The Office of the Attorney General was created by the Judiciary Act of 1789 , as a one-person part-time position.  The Act specified that the Attorney General was to be "learned in the law," with the duty "to prosecute and conduct all suits in the Supreme Court in which the United States shall be concerned, and to give his advice and opinion upon questions of law when required by the President of the United States, or when requested by the heads of any of the departments, touching any matters that may concern their departments."