District of Columbia District Attorney Establishment Act of 2003 - Amends the District of Columbia Home Rule Act to establish the Office of the District Attorney for the District of Columbia, to be headed by the District Attorney (DA) for the District.
Makes the DA the chief legal officer for the District to: (1) prosecute the District's local criminal laws, including violations committed by both adult and juvenile offenders, and perform any related functions; and (2) perform civil enforcement and other legal functions as provided by local law.
Specifies the qualifications for DA, including residence and domicile in the District. Prohibits the DA from engaging directly or indirectly in private practice.
Requires the District Attorney to be elected to a four-year term on a partisan basis by the registered qualified electors of the District; except that within 30 days after the enactment of this Act, the Mayor, by resolution, shall appoint a District Attorney to serve until succeeded by an elected District Attorney.
States that nothing in this Act shall affect the authority of the Attorney General or the U.S. Attorney for the District to exercise jurisdiction concerning violations of Federal laws.