President Carter will nominate J. Jerome Bullock, a 29-year-old Georgia native and graduate fo Howard University School of Law, as the new U.S. marshal for the District of Columbia, the White House announced yesterday.

If confirmed by the Senate, Bullock would replace George K. McKinney, who was nominated by President Nixon in 1973. Yesterday's White House announcement made no mention of McKinney. Nor did it provide any details of why Bullock was selected for the post.

As the U.S. marshal, Bullock would supervise about 50 deputies who serve legal papers, transport prisoners and provide protection in both the U.S. DIstrict and D.C. Superior courts.

Bullock, contacted yesterday at the headquarters of the U.S. Marshals' Service, where he is on the legal staff, would not comment on his impending appointment. He said he had not been officially notified by the White House.

Born in Hogansville, Ga., and a legal resident of Dublin, Ga., Bullock has lived in Washington since 1972. While attending the Howard law school he was employed by the Department of Transportation and one of its agencies, the Federal Aviation Adminiistration, and by the Department of Justice.

Since receiving his law degree, he has worked for the Internal Revenue Service and the Marshals' Service. An Army veteran, he also is a graduate of Tuskegee Institute.