Little did Rick Berman suspect that when he cast the star of Night of the Comet to be his Number One, he had unwittingly birthed Winnebago ManIN SPACE. Not long into VOY's run, Robert Beltran (Chakotay) stopped playing Mister Nice Guy and openly expressed his loathing of the show's plot, his co-stars (he only signed on to act alongside Geneviève Bujold), the producers, himself for playing such a formulaic role, and most of all you for watching it. His co-stars fired back in separate interviews, and the showrunners publicly told him to muzzle it, but they refused to grant Beltran the satisfaction of killing him off. Beltran saw out the entirety of his contract. This would not be the last time actors rebelled against Brannon Braga - see Enterprise.
Garrett Wang was almost as lethargic as Beltran, which is part of the reason why Harry Kim was never promoted. The producers didn't fire him, either (for publicity reasons), but he pointedly did not direct a VOY episode despite many requests.
Remember how an additional cast member and second pilot revitilized Deep Space Nine? Well, lightning managed to strike twice, but Seven's arrival only aggravated the prexisting tensions in the cast. Mulgrew was reportedly ticked about the show's focus shifting toward Seven of Nine, not so much out of dislike for her svelte usurper (she admitted the character saved VOY from cancellation) as resentment over sacrificing time with her family for a TV series Janeway no longer starred in.
The Danza: Kate Mulgrew was hired as a last minute replacement for Nicole Janeway (played by Geneviève Bujold) and she asked to have the first name changed to her full first name, Kathryn. Janeway's first name had originally been Katherine (note the different spelling) while the series was in development, but was changed to Nicole when the French-Canadian Bujold was cast in the role. The creators asked Mulgrew which of the two she would prefer, and she opted for a slightly altered version of the originally planned name.
Chakotay is often called 'Woodentop' (or variations thereof) due to his acting skills (or, more charitably, the limits the scripts imposed on the skills he had). More affectionate nicknames one might hear include Chak/Chuck, Commander Tat-face, and maybe Commander Studmuffin.
Seven of Nine's nicknames tend to focus on her... attributes, "38-of-D" and "Six of Nine".
Neelix has one too. But it's not really repeatable in polite company... (HINT: It has to do with how useful his mind is, and what his head looks like...) SF Debris prefers to call him "Hedgehog," or "S**thead."
Harry Kim is called, both by people who hate and love him, "The Dweeb."
Due to the cost of building VOY's bridge, converting the old TNG sets, reshooting the scenes shot with Geneviève Bujold and Janeway's hair debacle, some very pricey special effects scenes and a substantial amount of location filming, "Caretaker" had a final budget of US$23 mil, making it the most expensive episode in the history of Star Trek. When adjusted for inflation, it proved even more expensive than The Wrath of Khan. A running gag on-set was, "I wonder if we'll get this pilot shot before the series is over."
Ronald D. Moore, one of the patron saints of Star Trek, worked on 1 1/2 episodes of Voyager after Deep Space Nine ended. There was a well publicized falling-out between him and Brannon Braga over what the appropriate "mood" Voyager should be, such that he left. (Although they smoothed things over much later on.) Many of Moore's suggestions for Voyager were later incorporated into Battlestar Galactica (Reimagined). Hence, perhaps, the push-pull relationship between President "Toss 'Em Out the Airlock" Roslin and Commander "Strong & Silent Type" Adama (which is not unlike Janeway/Chakotay's relationship).
Braga did say that if Voyager was up to him, the show would have frequently been like the fan favorite episode "Year of Hell."
At the end of season three, either Harry Kim or Kes was slated to be killed off to make room for new character Seven Of Nine. Neither were killed off in the season finale, but the more likely candidate, Harry Kim, was seriously injured so that he could die in the fourth season premiere. Between seasons, Garret Wang ended up listed on Entertainment Weekly's list of 100 Hottest Celebrities, and the Executives mandated that he had to stay — so they wrote out Kes instead. This is especally ironic given Rick Berman's mandate that the alien characters be more interesting than the human ones.
According to Jennifer Lien, she had recently given birth before her audition. The execs were thus floored when her breasts shrank down to normal size.
The ending of "Basics" originally had Maj Cullah and Seska's baby die, and Seska escaping with Lon Suder in tow. As it turned out, the exact opposite happened. The writers wanted to close the book on the Kazon due to plummeting ratings. In addition, Jeri Taylor wasn't fond of Suder's character; hence his Redemption Equals Death arc.
"Non Sequitur" was originally supposed to feature Counselor Troi as the one grilling Harry Kim in the alternate timeline instead of yet another random Admiral. The creators were unable to get Marina Sirtis on short notice. (She did appear with Reg Barclay a few seasons later.)
Before getting the role of The Doctor, Robert Picardo originally auditioned for the role of Neelix.
Jeri Ryan has said that she read two different scenes when she auditioned for Seven of Nine. One was the rather notorious Do You Want to Copulate? scene, which ended up being filmed (and she admits to hating to this very day.) The other was apparently a really beautiful, touching scene where Seven first experiences laughter, and she seems to honestly regret that scene never made it to film. Other actresses who auditioned for Seven were Hudson Leick and Claudia Christian.
Captain Janeway's actress Kate Melgrew has said she thinks Janeway is bipolar due to the character's inconsistent characterization.
Garret Wang campaigned to be the first gay Starfleet officer, but the execs said no way. (Similar instances happened on TNG and ENT.) His own view is that Harry's a closeted gay man who pursues unattainable women as a means of avoiding his feelings for Tom.
Robert Beltran jokingly said in one interview that Chakotay was a homosexual. For fans of slash fiction, this is the last bit of evidence needed to confirm that Chakotay and Paris are bitter ex lovers.