We all know that ultimately his position was Chief, whether that be of the Transporter Room on the Enterprise-D or of engineering on Deep Space 9. What seems clear is that, from the very beginning, the writers did not know what to do with O'Brian, or indeed what purpose he was serving.
When we first see him in the pilot episode of The Next Generation: he is at the com station of the battle bridge wearing a RED uniform! He was not a principle cast member and therefore it was assumed he was there as cannon-fodder. At that time he wore one pip (Ensign).
The next time we see O'Brian, he has apparently transferred departments and wears gold (a much safer option), but now appears to be a lieutenant!
|Season 1 TNG: Ensign O'Brian, The Red Shirt!|
|Season 2 TNG: Lt. O'Brian in Gold|
Rather than a background extra/lacky he was given the prestigious job of sounding card to the Bridge crew, usually over a game of poker, probably because of his 'every man' image and accent - a role that he was used for many times in the later DS9 years. With that role would have to come a back story, and for O'Brian, a family too. As TNG continued, 'The Chief' as he was now known, seemed to randomly revert back to an Ensign for no apparent reason and with no explanation! The character makes references to being an un-commissioned officer and not a graduate of the academy which did not fit the rank he seemed to be carrying.
|Season 3 TNG: Ensign O'Brian?|
Now, all the confusion as to his rank was cleared up on more than one occasion in Deep Space Nine when he made numerous references to being non-commissioned, and to have never attended Starfleet academy. He points out that even Ensigns don't need to call him sir as he is not an officer. All this however does not explain the early Next Gen muddle. Off course its likely to be the writers finding their feet and once they realised Colm Meany would be a semi regular reoccurring character, they settled him in to a nice back story. This is not of course a Star trek answer and you know what us Trekkies can be like when it comes down to the fine details.
If any one does have a genuine Star trek explanation, then please get in contact...The Truth Is Out There!
|Season 6 DS9: Chief Petty Officer O'Brian|