She entered private practice in Washington, D.C., and then became a trial attorney at the United States Department of Justice Civil Division from 1963 to 1967.

[3] As the chief judge of the United States District Court for the District of Columbia, the Washington Post referred to Johnson as a "Key Player" in the 1998 grand jury investigation of President Bill Clinton due to her having to rule on a raft of motions relating to the investigation by independent counsel Kenneth W.

[1] Specifically, Johnson ruled that President Clinton's right to executive privilege was outweighed by Starr's legitimate need for evidence.

[1] Johnson also oversaw the conviction of Rita Lavelle on charges of making false statements, obstruction of a congressional investigation, and perjury and sentenced her to prison.

[6] Additionally, in sentencing former congressman Dan Rostenkowski to 17 months in prison for mail fraud, she told the once-powerful chairman of the House Ways and Means Committee in 1996 that “you capriciously pursued a course of personal gain for you, your family and your friends.