Most Star Trek Captains are introduced fully-formed and already settled in their rank. Star Trek: The Original Series never showed Kirk's promotion to Captain, and Star Trek: The Next Generation began with Captain Jean-Luc Picard (Patrick Stewart) already in command of the USS Enterprise-D. Same with Star Trek; Voyager's Captain Kathryn Janeway (Kate Mulgrew), Star Trek: Enterprise's Captain Jonathan Archer (Scott Bakula), and Star Trek: Strange New Worlds' Captain Christopher Pike (Anson Mount).
Other Star Trek characters were promoted to Captain off-screen. There were no ceremonies shown for Commander William T. Riker (Jonathan Frakes) or Chakotay (Robert Beltran) becoming Captains. The same goes for Worf, who was reintroduced as a Captain in Star Trek: Picard. Spock (Leonard Nimoy) and Montgomery Scott (James Doohan) became Captains off-screen. However, Star Trek has shown the following characters' promotions to Captain, and an Admiral get busted down back to Captain.
7Commander Benjamin Sisko Was Promoted To Captain On Star Trek: Deep Space Nine
Star Trek: Deep Space Nine Season 3, Episode 26 - "The Adversary"
It was never quite fair that Benjamin Sisko began Star Trek: Deep Space Nine as a Commander. The logic of Star Trek's producers was that starships have Captains and space stations like Deep Space Nine are run by Commanders. But Avery Brooks' portrayal of Sisko was always that of a Commander-in-name-only. Along with getting his own starship, the USS Defiant, in Star Trek: Deep Space Nine season 3, seeing Ben officially become Captain Sisko was immensely satisfying, if overdue.
6James T. Kirk Was Promoted To Captain In Star Trek's Kelvin Timeline
Star Trek (2009)
J.J. Abrams' Star Trek (2009) was James T. Kirk's (Chris Pine) origin story in the alternate Kelvin timeline, and it culminated with Kirk being promoted to Captain of the Enterprise. The bewildering way Kirk, who started as a Starfleet Academy Cadet, rose with breakneck speed to become a Captain is part of the fun of J.J. Abrams' Star Trek movie reboot. Kirk's promotion in front of the assembled Starfleet Academy student body is amusingly buttoned by Admiral Christopher Pike (Bruce Greenwood) telling his protégé, "I am relieved."
Just a year later, Captain Kirk would be demoted by Admiral Pike after Jim broke the Prime Directive and lied about it at the start of Star Trek Into Darkness. However, Pike's murder by Khan Noonien Singh (Benedict Cumberbatch) led to Kirk being reinstated as Captain of the Enterprise. In Star Trek Beyond, Captain Kirk applied to become Vice Admiral in charge of Starbase Yorktown, but he changed his mind and kept his rank to become Captain of the new USS Enterprise-A.
5Commander Saru Was Promoted To Captain In Star Trek: Discovery
Star Trek: Discovery Season 3, Episode 3 - "People Of Earth"
Commander Saru (Doug Jones) served as Acting Captain of the USS Discovery after the death of the Mirror Universe impostor posing as Captain Gabriel Lorca (Jason Isaacs) in Star Trek: Discovery season 1. Although the USS Discovery's Captaincy was a game of musical chairs, Saru was the reliable stalwart who led his starship into the 32nd century at the end of Star Trek: Discovery season 2. Not long after arriving in the year 3189, Saru was officially made Captain of the USS Discovery.
However, the first Kelpien in Starfleet relinquished Discovery's Captain's chair to return to his homeworld of Kaminar with Su'Kal (Bill Irwin). Back aboard the USS Discovery, Captain Saru accepted the First Officer position before becoming a Federation Ambassador. At the end of Star Trek: Discovery season 5, Saru married Ni'Var's President, T'Rina (Tara Rosling), and became Admiral Saru. Audiences got to witness Saru's many promotions throughout Star Trek: Discovery.
4Commander Michael Burnham Was Promoted To Captain In Star Trek: Discovery
Star Trek: Discovery Season 3, Episode 13 - "That Hope Is You, Part 2"
At the end of Star Trek: Discovery season 3, Commander Michael Burnham (Sonequa Martin-Green) is promoted to Captain of the USS Discovery, replacing the departing Captain Saru. Burnham's roller-coaster ride to the Captain's chair was a central story of Star Trek: Discovery's first three seasons. From disgraced First Officer of the USS Shenzhou, to Starfleet's first mutineer, to unranked Specialist, to Commander, and finally, Captain, Michael Burnham was rewarded for her tireless heroism in repeatedly saving the galaxy 930 years apart.
Captain Burnham's promotion came with a new gray Starfleet uniform before Star Trek: Discovery season 4 gave her a red uniform.
3Commander Seven Of Nine Was Promoted To Captain In Star Trek: Picard
Star Trek: Picard Season 3, Episode 10 - "The Last Generation"
Commander Seven of Nine (Jeri Ryan) was prepared to quit Starfleet when she was shocked that the late Captain Liam Shaw (Todd Stashwick) recommended her for promotion to Captain. At the end of Star Trek: Picard season 3, Seven of Nine not only received four pips, but she was also named Captain of the USS Enterprise-G. Not bad for a former Borg Drone who was once rejected from Starfleet because of her past links to the Borg Collective.
Seven of Nine's promotion to Captain was made official by Captain Tuvok (Tim Russ), her former crewmate on Star Trek: Voyager.
2Commander Jack Ransom Promoted To Captain In Star Trek: Lower Decks
Star Trek: Lower Decks Season 5, Episode 10 - "The New Next Generation"
Star Trek: Lower Decks season 5 ended with Commander Jack Ransom (Jerry O'Connell) promoted to Captain of the USS Cerritos after Captain Carol Freeman (Dawnn Lewis) exited to lead Starfleet's multiverse explorations from Starbase 80, Ransom long desired the Captain's chair, and he wasted no time shaking things up by making Lieutenants Beckett Mariner (Tawny Newsome) and Bradward Boimler (Jack Quaid) co-First Officers.
Gwyndala (Ella Purnell) is named Captain of the USS Prodigy at the end of Star Trek: Prodigy season 2, but she is still a Starfleet Academy Cadet, and it's unclear if her promotion is a full Captaincy.
1Admiral James T. Kirk Was Demoted To Captain
Star Trek IV: The Voyage Home
While Star Trek didn't show James T. Kirk's promotion to Captain of the Enterprise in Star Trek's Prime Timeline - something that may one day happen in Star Trek: Strange New Worlds - Admiral Kirk's demotion to Captain happened in Star Trek IV: The Voyage Home. Admiral Kirk broke numerous Starfleet regulations in Star Trek III: The Search for Spock, including hijacking the USS Enterprise to rescue Spock (Leonard Nimoy) from the doomed Genesis Planet.