In 1987 Blake became a United States magistrate judge of the District of Maryland.

She was nominated by President Bill Clinton on May 4, 1995, to a seat vacated by John R. Hargrove Sr. She was confirmed by the United States Senate on August 11, 1995, and received her commission on August 14, 1995.

[2] Judge Blake presided over the infamous Baltimore Gun Trace Task Force case.

[3] She is portrayed in the final episode of the HBO miniseries "We Own This City" which depicts the events surrounding the case.

[4] In October 2020, Judge Blake struck down a constitutional challenge to Governor Hogan's executive order that mandated state contractors were not allowed to engage in a political or economic boycott of Israel in their business or personal life.