In 2358, as captain of the USS Pegasus, Pressman was placed in charge of testing an experimental phasing cloaking device, which had been developed by a secret group at Starfleet Security in direct violation of the Treaty of Algeron, which banned the use of cloaking technology aboard Federation starships. In response to this illegal activity, the crew of the Pegasus mutinied against Pressman and attempted to gain control of the ship. Pressman and a small group of officers, including a young Ensign William T. Riker, were able to escape the ship by fighting their way to the escape pods. From there, they observed what appeared to be the destruction of the ship.
When Pressman and the surviving crew returned, they faced a board of inquiry with the Judge Advocate General about the mutiny and the loss of the ship. He ordered the rest of the crew not to divulge the nature of the experiment. The report from the inquiry was classified and Pressman did not face charges.
Pressman eventually obtained a position within Starfleet Intelligence. By 2370, he became a rear admiral.
Attempt to retrieve the Pegasus
In 2370, when Intelligence operatives within the Romulan High Command learned that the Romulans had become aware of the Pegasus' experiment, Pressman was chosen to head up the mission to retrieve the ship. He boarded the USS Enterprise-D, determined to find it before the Romulans. Reuniting with Riker, who by this point was first officer of the Enterprise-D, Pressman attempted to use his relationship with Riker for the mission, ordering him to take part without telling Picard and the Enterprise crew. Feeling unable to continue his role in the conspiracy, Riker revealed the true nature of Pressman's mission to Captain Picard, who promptly ordered Pressman placed under arrest. Although he and his cohorts were facing a court martial for their role in the illegal activities, Pressman warned Picard that he had "a lot of friends" at Starfleet Command, to which Picard indifferently replied "You're going to need them." (ENT: "These Are the Voyages..."; TNG: "The Pegasus")
Pressman was portrayed by veteran actor Terry O'Quinn.
In the short story "Orphans", which was published in the anthology book Strange New Worlds 9, it was revealed that Pressman was recruited by Section 31 after his court martial. In 2374, he and Doctor Julian Bashir were sent to the planet Angosia III to recruit super-soldiers such as Roga Danar for a mission to Gateway to prevent the Dominion from seizing the Guardian of Forever. Pressman used a salvaged Romulan vessel with a working cloaking device as his transport.