This was an INSTANT FAVOURITE when it first appeared in “Darmok”. It’s Jean-Luc’s ‘casual Captain’s uniform’ similar to this on Kirk and Archer:
I love that suede and gold lamé (and leather in the first appearance of Jean-Luc’s jacket) are considered more casual than the standard uniform.
And I like that its appearance in “Darmok”, “Liaisons”, and “Attached” implies that Jean-Luc has a sixth sense for when he’s going to be kidnapped and will have to sleep on the ground, and should thus dress in his more comfortable uniform.
The design also works well as a bridge between the TNG uniforms and the DS9/Voyager version. I like to imagine Jean-Luc was part of a new uniform design pilot program – a perk as Captain – and sent notes to Starfleet.
And this jacket could be worn in our century, over a cute lbd (or l-grey-d) and be just as fashionable.
Per MemoryAlpha (quoting a Cinefantastique interview with producer David Livingston):
“It’s just something a little more casual for the Captain. The genesis of the design was that submarine and aircraft commanders sometimes have a jacket that’s special.”
So first of all, the U.S. Navy has this really cool online uniform app that details 15 different navy uniforms, none of which is relevant to this ask, but is nonetheless way more fun than I’d expect.
Now, some jackets:
The pea coat, now a civilian fashion staple, debuted in a European navy (both the Dutch and British have histories on it) some 200-250ish years ago. It remains an option in the navy, on the left is the enlisted version, and center is the officers’ bridge coat (longer and with shiny buttons).
But Jean-Luc’s jacket most resembles the ‘Eisenhower Jacket’, right, which was created for the army during WWII (but is also worn in the navy). Neat!
Picard also wears an alternate Captain’s uniform in the film First Contact, a vest instead of a jacket.
This uniform is not only more casual, it is better suited to action and even resembles the street level action hero aesthetic Jean-Luc tends toward.
It makes sense that when presented with the Borg, he changes into something that is both more comfortable and familiar.
As the action progresses, Jean-Luc loses his layers, parallel with his journey through time and trauma. And as the Phoenix flies into history, Picard and Data emerge from fire.