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This page details Miles O'Brien in the primary universe; for the Miles O'Brien in the mirror universe see Miles O'Brien (mirror); for the Miles O'Brien in all other alternate universes see Miles O'Brien (alternates).

Miles O'Brien
Character image.
Chief of Operations Miles Edward O'Brien in 2375
Full name: Miles Edward O'Brien
Species: Human
Born: 2328
Affiliation: Federation, Starfleet
Mother: Megan O'Brien
Father: Michael O'Brien
Sibling(s): Bill O'Brien,
Cully O'Brien
Marital Status: Married
Spouse(s): Keiko O'Brien
Children: Molly O'Brien,
Kirayoshi O'Brien
Other relatives: Maia O'Brien
(great great granddaughter)
Occupation: Starfleet officer
Previous Assignment: tactical officer,
USS Rutledge;
transporter chief,
USS Enterprise-D;
chief of operations,
Deep Space 9;
Starfleet Corps of Engineers
Final Assignment: Command Master Chief,
Deep Space 9 (II)
Rank: Command Master Chief Petty Officer
Insignia: Starfleet insignia. Uniform rank image.
Character image.
Chief Miles O'Brien in 2364

Miles Edward O'Brien was a 24th century Human man, born on September 1, 2328. He has served Starfleet as tactical officer aboard the USS Rutledge during the Federation-Cardassian War, transporter chief aboard the USS Enterprise-D from 2364 to 2369, chief of operations aboard starbase Deep Space 9 from 2369-2375, chief engineer of the USS Defiant from 2371 to 2375, and as an instructor at Starfleet Academy beginning in 2376. In 2383, O'Brien was assigned to oversee construction of the second Deep Space 9 space station.


Early life[]

Miles O'Brien was born to Michael and Megan O'Brien, and had two brothers, Bill and Cully, and more than one sister.

In his youth, O'Brien built ships in bottles.

Miles, having grown up in a traditionally Irish setting was a very practical man. Most times (when feasible) he preferred an au naturel approach to food, recreation etc. rather than tech - even though that was a trade he specialized.

His pragmatic, "everyman" approach carried over into his DS9 posting. As an enlisted crewman, he saw himself as an equal to his fellow crewmates superior or subordinate and disliked titles, such as "Sir". Always innovative and open to new concepts, O'Brien believed in engineering to be simple for the average Layman.

His mother raised him to follow the advice about combining talking with eating, "You end up doing neither very well!."


O'Brien had a fondness for the sport of kayaking and enjoyed it as a holodeck program.

He also enjoyed racquetball and darts.

Musically O'Brien played the cello and performed several concerts on his various assignments.

Along with his friend, Dr. Bashir, O'Brien enjoyed historical re-creations on the holodeck. O'Brien once created a model of the Alamo.

The Rutledge[]

O'Brien was aboard the Rutledge during the Cardassian border conflicts and was present to witness the aftermath of the Massacre on Setlik III.

The Enterprise-D[]

O'Brien then transferred to the USS Enterprise-D, where he served Captain Picard as a relief Flight controller during the Farpoint Mission. After the mission he served as part of the Enterprise's security and operation divisions, acting mainly as a Transporter chief. On stardate 43423.6, O'Brien was coerced telepathically by Zadeus to destroy one of the two queens with a transporter. However, Commander Forthol noticed O'Brien was acting strangely when he gave up a winning hand in a poker game with Commander Riker. O'Brien was then freed when Riker, Captain Picard, Commander La Forge and Forthol stopped him from carrying out Zaedus's murder plan.

Deep Space 9[]

O'Brien was assigned to Deep Space 9 in 2369. In early 2370, during a time of political upheaval on Cardassia, the crew of the Cardassian ship Swift Striker attempted to destroy Deep Space 9 by planting a bomb on its anti-matter reactor. O'Brien worked with Berat, a member of the Cardassian crew who had sought asylum on the station, to remove the bomb and then attached it to the Swift Striker, resulting in the ship's destruction. O'Brien was so impressed with Berat he offered him a position on the station, although Berat chose to return to Cardassia when the political situation changed.

Sometime prior to the Battle of Cardassia, Miles was approached to take the position of Professor of Optronic Systems Engineering at Starfleet Academy, a posting he took after some thought, breaking the news to his friend Julian Bashir in the midst of battle.

Starfleet Academy and the Corps of Engineers[]

In 2376, while teaching at Starfleet Academy, O'Brien assisted the Starfleet Corps of Engineers when an alien artifact threatened to destroy San Francisco.

In September of 2376, Miles, his wife Keiko, and their children Molly and Kirayoshi, visited Joseph Sisko in New Orleans and later accompanied him to Bajor to attend the birth of his grand-daughter.

While in the Bajoran system, the Chief helped out his old friends on DS9 during the Parasite crisis, and attended Bajor's induction into the United Federation of Planets.

O'Brien was later detached to the Starfleet Corps of Engineers on the planet Cardassia as a part of the Federation's relief efforts, while Keiko was in charge of the planet's botanical renewal efforts following the Dominion War.

The new Deep Space 9[]

In 2383, following the destruction of Deep Space 9, O'Brien was reassigned as chief engineer of both the ground-based facility that substituted for it and the construction of the replacement station.

After construction was complete of the new Deep Space 9 O'Brien took over as chief engineer of the station.

In early 2386, O'Brien and Nog travelled to the space station Robert Hooke to visit O'Brien's old commanding officer Benjamin Maxwell, now working as the station's maintenance engineer. While there, they became involved when the station's head Anatoly Finch caused severe damage to the station as a result of a plan to sell his genetically engineered creature "Mother" to Romulan farmers. O'Brien and Nog arranged for the evacuation of most of the station's personnel, although Maxwell was believed dead in the station's destruction.

By 2387, O'Brien had been promoted to Command Master Chief Petty Officer, serving as Captain Ro's right-hand man.

Alternate timelines and realities[]

In an anti-time past created by Q, O'Brien was surprised in 2364 that Captain Jean-Luc Picard was aware that he had built model ships in bottles as a child. Unbeknownst to O'Brien, the captain had travelled back in time from 2370. Picard had learned of his interest in model ships from a conversation in 2366.

In an alternate timeline created by the USS Defiant being sent back in time to the 22nd century, the ship's crew, including O'Brien, settled on Gaia IV. He married Rita Tannenbaum ten years after the Defiant's crash and was the last member of the crew to give up hope about returning to the 24th century. Their descendants included Miranda O'Brien and their great-great-great-great-great-granddaughter Molly. The name "Molly" had been passed down through the O'Brien family for 200 years.

In another alternate timeline in which the Cardassian Union did not withdraw from Bajor in 2369, Chief O'Brien received a commission as a Lieutenant when he became the chief engineer of the USS Enterprise-E in 2373 after Lieutenant Commander La Forge transferred to the USS Sugihara. He was killed six months later when the Enterprise was destroyed in the Bajor system by a Dominion ship commanded by Omet'iklan.

In an alternate reality in which the Borg emerged victorious from the Battle of Wolf 359 in 2367, O'Brien still served aboard the Enterprise-D. Like his primary universe counterpart, this O'Brien was married to Keiko O'Brien and had a daughter, Molly, though they were killed in a Borg attack.

When the crew of his Enterprise-D encountered the crew of the Enterprise-D of the primary universe, this O'Brien knocked out his counterpart and unsuccessfully attempted to take his place.

Miles O'Brien in an alternate reality

In another alternate reality, Federation and Dominion delegations met on Deep Space 9 to negotiate a treaty in response to the Dominion's peace overtures in 2371. However, during the talks, Odo was murdered with a phaser. Consequently, the negotiations broke down and the Dominion launched an attack on DS9. Both his wife Keiko and his daughter Molly were killed during the attack, leaving O'Brien devastated. Although the Federation forces were eventually able to push the Jem'Hadar back through the Bajoran wormhole, the Dominion was able to capture Commander Benjamin Sisko, Major Kira Nerys and Doctor Julian Bashir.

He assisted the Trill diplomat Curzon Dax in modifying the USS Defiant to travel to alternate realities. Curzon then began to search the multiverse for another version of Odo. Curzon's plan was to return to his own reality with this other Odo, who would claim that he had faked his own death in order to expose the traitor aboard DS9. After arriving in the primary universe, Curzon attempted to recruit Odo for that purpose but Commander Sisko believed that interfering in the affairs of another universe would violate the Prime Directive. Refusing to take "no" for an answer, Curzon kidnapped Odo while he was regenerating, commandeered the Defiant of the primary universe and returned to his own reality. In accordance with Curzon's plan, Odo assumed the identity of his murdered counterpart. Besides Curzon, O'Brien was the only person aboard DS9 who was aware that this Odo was from an alternate reality.

Kelvin timeline[]

Miles O'Brien in an alternate reality

In an alternate reality created by Q, O'Brien was the first officer under his wife, Captain Keiko on board the USS Defiant. He then rescued Sisko, Captain Kirk and his party after Changelings had murdered Chancellor Worf using a shuttle. O'Brien was then assisted by Commander Scott in fixing the warp drive. The two then discussed engineering.