
In that episode, it is clear that the classic Irish tune " The Minstrel Boy" plays a major part of his journey as a character: an innocent man thrown into the destructive nature of war. O'Brien does not remember how many Cardassians he killed, because he killed so many ( Star Trek DS9: "The Inquisition"). The TNG episode " The Wounded" establishes that O'Brien served as tactical officer aboard the USS Rutledge during the Cardassian War and that he was emotionally scarred by the Cardassians' massacre of hundreds of civilians on Setlik III. In the DS9 episode " Invasive Procedures", it is revealed he has two brothers. O'Brien can also be seen playing the cello as part of Data's string quartet early in the TNG episode " The Ensigns of Command". However, a few days before he was scheduled to start classes there, he enlisted in Starfleet. His father, Michael O'Brien, wanted him to play the cello, so he pursued this and was eventually accepted into the Aldebaran Music Academy (revealed in DS9 episode " Shadowplay"). He claims descent from Brian Boru, the famous Ard Rí, or High King of Ireland (and founder of the O'Brien Clan).

The backstory of the character states that Miles O'Brien was born in Killarney, a town in County Kerry in Ireland, Earth, in September 2328.

Appearing on and off in subsequent episodes, mainly operating the ship's transporters, it wasn't until the second-season episode " Unnatural Selection" that Meaney's character was named, and the second episode of season 4, " Family," before the character was given a first name, and his personal life began to be developed. 3.3 Depiction in Star Trek: Deep Space NineĪccording to Colm Meaney, at first O'Brien "was just there, not really established as a character, and that went on for a bit." He has a few lines in the pilot TNG episode, " Encounter at Farpoint".3.2 Depiction in Star Trek: The Next Generation.
