She was 79.
Her brother, Lionel Holloway of Louisiana said she suffered a stroke and died Sunday at his home in Lake Charles, The New York Times reported. Johnson's husband, Julius, a retired federal administrative law judge died in 2008, and her brother was her only immediate survivor.
Born Normalie Loyce Holloway to a poor family in Louisiana, Johnson moved to Washington with her mother's encouragement and lived with a cousin while she trained as a teacher. She attended Georgetown University Law School at night while teaching during the day.
In 1998, Johnson made a number of rulings that gave Ken Starr, the special prosecutor investigating President Bill Clinton's conduct, power to question Clinton's aides and to see documents drawn up by lawyers for White House intern Monica Lewinsky.
Johnson could be tough on those in power, scolding former Rep. Dan Rostenkowski, D-Ill., when she sentenced him for mail fraud. She told him he had "stained" his family and friends.
But she showed compassion to defendants like a young mother charged with tax evasion who apparently got into trouble because of drug problems.
"Those children need you more than they need anything else," Johnson told the young woman, urging her to stick with drug treatment.