As a lieutenant, in 2369, he was assigned by Starfleet Security to the Bajoran space station Deep Space 9 following a three week journey to arrive at the station. His first assignment was to ensure a deuridium shipment from the Gamma Quadrant passed through the station safely.
Following his arrival, he observed Constable Odo and Quark casually discussing the deuridium shipment. Primmin commented on Odo's "interesting technique", inquiring to the station's Bajoran security chief, "do you always get ready for an important operation by leaking word about it to the local black market?" Following his introduction, he and Odo arranged to discuss the security arrangement in Odo's office at 17:00.
Later, he discussed the security arrangement with Commander Benjamin Sisko, offering his unprompted opinion of Odo, believing that he was sure Odo was "very good at keeping order down there on the Promenade," but considered Odo's heading up security in the matter of the deuterium shipment to be "a little over his head". After recalling Odo's "interesting technique" observed at Quark's, he flat out told the commander that "it's not they way they taught us at the Academy." Sisko then reminding Primmin that they were both there as "guests of the Bajorans," and explained to him that "you don't have to forget what you learned at the Academy, you just don't throw it in anyone's face here." Sisko then suggested that he might actually learn a thing or two from Odo, adding that he wanted the two of them to coordinate with the Kobliad Security officer Ty Kajada, who was already aboard the station.
In he and Odo's later meeting, Primmin apologized to Odo for getting off on the wrong foot, before acknowledging that the station was Odo's bailiwick, and that he didn't mean to be throwing his weight around. Odo dismissed most of Primmin's gestures, before he agreed to share his security arrangements.
Odo took Primmin's assignment there as an insult, believing Starfleet had no faith in his abilities. The Constable initially offered his resignation because of the issue, but soon came to respect Primmin after the Starfleet officer discovered a subspace crossover shunt, placed there by the Kobliad criminal scientist Rao Vantika. Had the device been activated, it would have crippled the station for close to an hour, thereby giving Vantika time to steal the deuridium shipment. (DS9: "The Passenger")
Shortly after these events, Primmin was the only senior officer left after the Wadi transported Sisko, Dax, Bashir, and Kira into Chula, one of their game environments. Primmin initially thought that the senior staff partied with the Wadi all night, until Odo alerted him that they were missing and ordered Primmin to sweep the station to locate them. (DS9: "Move Along Home")
Primmin was played by actor James Lashly.
The invention of the Primmin character came about because Colm Meaney was about to become absent, unable to appear as Chief Miles O'Brien. Michael Piller noted, "We had always talked about this Primmin character because Colm was going away to do a movie." (The Official Star Trek: Deep Space Nine Magazine issue 3, p. 12) Robert Hewitt Wolfe recalled, "We needed someone there for people to talk to, and we wanted to show what the chain of command was, as far as station security is concerned. The Primmin story did that." ("Robert Hewitt Wolfe - Writer/story editor", The Official Star Trek: Deep Space Nine Magazine issue 8)
The script for "The Passenger" states the pronunciation of Primmin's name as "PRIH-muhn". It goes on to describe him as, "a Starfleet security officer in his mid-thirties. He has a friendly face, an easygoing smile and a passing resemblance to a teddy bear." This would put Primmin's year of birth around 2334. 
Primmin became a suspect in "The Passenger" while the episode was being written. "What we didn't realize, until I started going into my rewrites, was that Primmin would be a good red herring," said Michael Piller. (The Official Star Trek: Deep Space Nine Magazine issue 3, p. 12)
Primmin was included in "Move Along Home" as Colm Meaney remained unavailable, still filming a movie. Following the making of "Move Along Home", Robert Hewitt Wolfe stated about Primmin, "I like that character. He's sort of the good ol' boy. I don't know if he'll be back; we have no plans to do so right now." ("Robert Hewitt Wolfe - Writer/story editor", The Official Star Trek: Deep Space Nine Magazine issue 8)
Though Primmin only appeared in two episodes of Deep Space Nine's first season and was not seen again during the series' run, a similar character, Michael Eddington, later debuted in season three premiere "The Search, Part I" and became a recurring character. Eddington was another Starfleet security officer, and Odo initially had the same reaction to him as he does to Primmin in "The Passenger".
In his review of "The Passenger", Star Trek author Keith R.A. DeCandido wrote that he would have liked to have seen more of Primmin in future episodes, particularly in relation to the conflict with Odo, and also thought the character was, "the only compelling element of a very run-of-the-mill plot." 
In the Pocket DS9 novel The Big Game, Starfleet posts a communique for a Human fugitive named L'sthwan which Primmin then briefs to Odo. Though the communique is very vague, the crew of Deep Space 9 become concerned that L'sthwan might be on the station when a Romulan female who had arrived to play in The First Annual Deep Space Nine Poker Tournament is murdered while in a practice poker session. Despite Primmin's objections, Odo participates in the game, and is able to capture L'sthwan. Following this, Odo asks Primmin to guard him in the station's brig.