The United States Attorney for the Southern District of Mississippi represents the United States in civil and criminal litigation in the court. As of January 20, 2021[update] the Acting United States Attorney is Darren LaMarca.
Chief judges have administrative responsibilities with respect to their district court. Unlike the Supreme Court, where one justice is specifically nominated to be chief, the office of chief judge rotates among the district court judges. To be chief, a judge must have been in active service on the court for at least one year, be under the age of 65, and have not previously served as chief judge. A vacancy is filled by the judge highest in seniority among the group of qualified judges. The chief judge serves for a term of seven years or until age 70, whichever occurs first. The age restrictions are waived if no members of the court would otherwise be qualified for the position.
When the office was created in 1948, the chief judge was the longest-serving judge who had not elected to retire on what has since 1958 been known as senior status or declined to serve as chief judge. After August 6, 1959, judges could not become or remain chief after turning 70 years old. The current rules have been in operation since October 1, 1982.