In 2267, while serving in the operations division, he was the portmaster of Starbase 11. That same year, Stone also served as the President of the Court in the first general court martial of a Starfleet captain in the history of the service.
In 2267, the USS Enterprise headed to Starbase 11 for a non-scheduled layover after being badly damaged from a recent encounter with a severe ion storm. As the Enterprise had higher priority than its sister ship USS Intrepid, Stone rescheduled Maintenance Section Eighteen to work on the former ship.
Stone found a discrepancy between Captain James T. Kirk's deposition regarding the death of Lieutenant Commander Benjamin Finney, and a significantly different computer record of the incident. Stone entertained a number of reasons why Kirk might have killed Finney, from negligence to malice. For a moment, Stone was willing to sweep the incident aside for the good of the service, by offering Kirk a permanent ground assignment. Incensed by the accusation and the very idea of Starfleet participating in a cover-up, Kirk maintained the error was in the logs and demanded his name be cleared.
In his capacity as President of the Court, Stone convened Kirk's court martial. The trial proceeded smoothly until the investigation of Spock suggested tampering on the Enterprise computers. Stone accepted defense attorney Cogley's suggestion that the court re-convene aboard the Enterprise. Confirmation of Spock's suspicions led to the revelation that Finney was indeed alive and still aboard the ship.
After Finney sabotaged the Enterprise and the spacecraft began to lose orbit, Stone refused to adjourn to the starbase, instead opting to actually share the risks the starship's crew faced. From the bridge, Stone and the court officers heard the "testimony" of Finney by monitoring his confrontation with Kirk. Once Kirk had defeated Finney and restored the ship's orbit, Stone dismissed the court. (TOS: "Court Martial")
This character was originally an unnamed "Harbormaster", written as such in early story outlines of "Court Martial" (which meanwhile had the working title "Court Martial at Star Base 811"). In the episode's first draft story outline (dated 2 May 1966), he was described as "a grouchy, elderly former flying officer, now grounded as overage and disposed to be prejudiced against Kirk for the simple reason that Kirk still holds command-flight functions and he does not." A revised story outline for the installment (dated 26 June 1966) characterized him as "a retired Star Ship captain himself, who is well aware of how easy it is to charge negligence or misconduct and how rarely there is any basis to such charges."
In the final draft and revised final draft of the script for "Court Martial", Stone was initially described as "a Negro, whose bearing marks him as a man accustomed to command. No longer a flight officer, his uniform is somewhat different from Kirk's." In the final draft script, Stone was twice referred to, in dialogue, as a "Portmaster", in regard to his duties at Starbase 11, and one of the two references was in a captain's log entry voiced by Kirk, which also characterized Stone as holding the rank of "senior captain". In the revised final draft script, the references to Stone as a "Portmaster" were edited out. Instead, he was referred to, in Kirk's log entry, as "the commander of Starbase 11... Commander Stone." However, he was still called a "Portmaster", albeit in the script's cast list. In a similar change of title, the final draft referred to Stone as "Chief Judge" at Kirk's court martial whereas the revised final draft called him "President of the Court" during those proceedings.
According to the reference book Star Trek Concordance by Bjo Trimble, Stone's first and middle initials were "L.T." The Star Trek Compendium by Allan Asherman and the comic book "Who's Who in Star Trek 1" also called him "L.T. Stone". This information may have been from an early draft of the script.
In the novel Vulcan!, by author Kathleen Sky, Stone's first name was established as "David". Cloak differed and called him "Aaron Stone". Preserver calls him "Robert Stone". The comic book story "Action of the Tiger" indicated he was later promoted to admiral.