He was chatting with a woman on the promenade and had later a drink in the replimat, when Li Nalas was rescued and brought aboard Deep Space 9. (DS9: "The Homecoming")
He was among the Starfleet officers in Ops during Sisko's speech in 2370. (DS9: "The Siege")
He was off duty and a guest in the Klingon restaurant on the promenade in 2370. (DS9: "Melora")
He had a meal in the replimat and was later off duty, when he appeared in civilian clothing in Club Martus. (DS9: "Rivals")
He joined a fellow Starfleet officer in the replimat when Garak and Doctor Bashir met there. (DS9: "The Wire")
He was talking to an alien bar patron in Quark's when Major Kira was forced to enjoy herself by CMO Julian Bashir. Later, he passed Kira on the Promenade shortly before the Major bumped into William T. Riker. He passed Riker and Kira again in the docking ringcorridor leading to the Defiant. (DS9: "Defiant")
He was on duty on board the Defiant during the meeting with the Karemma in the Gamma Quadrant. His console exploded when a Jem'Hadar fighter fired on the Defiant. He wasn't injured and able to continue his duty. (DS9: "Starship Down")
That year, he conferred with Worf while walking the station's corridors, when Worf was called by Odo and informed his brother Kurn had been shot by a Boslic freighter captain. (DS9: "Sons of Mogh")
He was a guest in Quark's when Brunt closed the establishment and took all property away from Quark. (DS9: "Body Parts")
This Starfleet command division crewman passed Lieutenant Dax and Major Kira on the Promenade in 2369. He smiled at Dax and said "Hello, lieutenant.". Dax smiled back at him and told Kira shortly after this she should get used to be a female again as she wasn't a female for over eighty years. (DS9: "Babel")
This Starfleet officer was played by Todd Feder. This character was scripted as "Starfleet male" and listed as "Federation male" in the end credits of the episode.
This crewman suffered from the aphasia virus in 2369. He was infected after a Bajoran device malfunctioned and infected Deep Space 9 while under Bajoran/Federation occupation. Together with a female companion he entered the infirmary and told Commander Sisko and the Doctor "View lost pile luck. Away tunnel back the garden.". (DS9: "Babel")
This Starfleet officer was played by Lee Brooks. This character was scripted as "Starfleet Aphasia Victim Two" and listed as "Aphasia victim" in the end credits of the episode.
She was present on ops when the crew witnessed the destruction of the Bok'Nor and when Calvin Hudson visited Sisko's office. Later she passed two Peliar Zel natives on the upper level on the promenade and passed the entry of Quark's, talking to another Starfleet officer. (DS9: "The Maquis, Part I")
She passed Garak and Bashir on the promenade, talking to another woman. She also visited the replimat and was eating with another officer. (DS9: "The Wire")
Off duty, she was on the promenade when a young Jem'Hadar came storming out of the infirmary and was very scared by the young alien who nearly ran her over. (DS9: "The Abandoned")
After the security on the station was brought back she was a guest at Quark's Bar, passing guests on the second level. (DS9: "Civil Defense")
This command division lieutenant served on ops in 2371 when Smiley abducted Commander Benjamin Sisko. Shortly before his abduction, Sisko took over the command of ops to this lieutenant. (DS9: "Through the Looking Glass")
It is unclear whether this officer exists in real life or was simply a figment of O'Brien's imagination, though the vivid picture in his head suggests O'Brien likely placed a real officer in that position.