George K. McKinney, who was the first African American to be appointed U.S. marshal for the District of Maryland, and whose career in federal service spanned more than four decades, died June 17 of leukemia at his home in Baltimore, his family said. He was 77.

Early in his career, Mr. Kinney was a deputy U.S. marshal for the District of Maryland and a special agent and polygraph examiner with the National Security Agency at Fort Meade. In 1973, he was appointed U.S. marshal for the District of Columbia — the third African American marshal to serve the district — by President Richard M. Nixon.

On April 18, 1974, U.S. District Judge John J. Sirica ordered Mr. McKinney to serve Nixon a subpoena to turn over White House tapes relating to the Watergate scandal.

Nixon’s chief defense counsel, James D. St. Clair, told Mr. McKinney that delivering the subpoena was unconstitutional. When Mr. McKinney threatened to deputize the White House Secret Service detail to comply with Sirica’s orders, the president’s attorney agreed to a meeting with Nixon.

Mr. McKinney wasn’t sure what the reaction would be from the man who had just appointed him U.S. marshal, and realized he could be fired. Ultimately, the president’s representatives accepted the subpoena.

George McKinney (BALTIMORE SUN)

From 1977 to 1994, Mr. McKinney held management jobs with the Justice Department in Washington. Some of the positions included serving as director of justice protective services, assistant director for physical security, senior security specialist, operations security officer and computer security officer.

In 1995, President Bill Clinton appointed Mr. McKinney as U.S. marshal for Maryland, the first African American to hold that position in the state since the founding of the U.S. Marshal Service in 1789.

Mr. McKinney retired in 2002 as U.S. marshal for Maryland. Since then, he had headed George K. McKinney Consultations, which advised on security and administrative operations for government and private and nonprofit organizations, as well as executive protection and security background investigations.

Mr. McKinney was also chief executive of Clamar, a property management organization, advising on personal and physical security matters.

George Kimbrough McKinney was born Dec. 16, 1934, in Providence, R.I., and raised in Boston, Petersburg, Va., and Richmond. After graduating in 1956 from Morgan State University in Baltimore, he served in the Army and rose to the rank of captain before his discharge in 1965.

His wife of 49 years, the former Mildred Sensabaugh, a Morgan State University professor of mental health, died in 2005. A son died in 1973. Survivors include four children; a sister; four grandchildren; and a great-granddaughter.

— Baltimore Sun