Leo Francis Walsh was an alias used by Harcourt Fenton Mudd in 2266.

Mudd was then engaged in the business of providing wives for settlers on Ophiucus III. According to Mudd, the real Leo Walsh was the man originally slated to captain his ship, but he "passed away, suddenly" before the trip. As he was taking the man's place, Mudd claimed he also took Walsh's name "in memoriam, as it were." (TOS: "Mudd's Women")

This character was only mentioned in dialogue.