Judge Walsh was appointed to the bench in Los Angeles, California in 2001, serving in the Central District of California, the largest trial court in the federal system. He has been the Chief Magistrate Judge since January 2016. Before becoming a Magistrate Judge, he served as a federal prosecutor in the U.S. Attorney’s Office in Los Angeles from 1996 to 2001. He also worked as an Assistant United States Attorney in the Civil Division from 1992 to 1996. From 1989 to 1992, he was a trial attorney with the U.S. Department of Justice in Washington, D.C. He began his career as a law clerk in the U.S. District Court for the Commonwealth of the Northern Mariana Islands in Saipan, where he served from 1985 to 1989. In addition to clerking  for District Judges Alfred Laureta and Alex R. Munson on that court, he also served as Judge Munson’s law clerk when Judge Munson was the Chief Justice of the High Court of the Trust Territory of the Pacific Islands. Judge Walsh teaches Pretrial Advocacy at the University of Southern California Gould School of Law.