Magistrate Judge Diane Lepley came to the Superior Court from a private practice specialized in criminal litigation. She represented indigent criminal defendants in the Superior Court of the District of Columbia (Superior Court) and in Federal Court. She is a former Director and Vice President of the DC Association of Criminal Defense Lawyers. Judge Lepley worked in all three branches of government. She worked for the United States Senate Committee on the Environment and Public Works, where she wrote articles about public works projects. Subsequently, as a Congressional Liaison at the National Bureau of Standards (now the National Institute of Standards and Technology), she analyzed federal legislation and testimony to be presented to the Congress. Following her graduation from law school, she served as the law clerk for the Honorable Tim Murphy in Superior Court.

Judge Lepley graduated from the University of Illinois in Champaign/Urbana with a Bachelor of Arts in English/Speech. She received a master's degree in speech communications from West Virginia University where her thesis examined the effect of language intensity on the art of persuasion by men and women. Judge Lepley received her Juris Doctor from George Washington University Law School.