Several recurring and one-shot characters from Babylon 5 are extremely popular among fans.
- Neroon was not originally part of the five year plan, having been created by D.C. Fontana in her script for the episode "Legacies." But JMS was so impressed by John Vickery's performance that he brought the character back several times, eventually making him an essential part of Delenn's story.
- In the episode "Spider in the Web," JMS gave Jeff Conaway a bit part as a security officer, simply wanting to help him get back on his feet after he kicked his heroin addiction that cost him his job on Taxi.note This worked out so well that his character got a name, Zack Allen, and eventually joined the main cast.
- Zathras (and his brothers Zathras, Zathras, Zathras, and the others...) only appeared in a few episodes, but he's beloved by the fans for his kooky personality and because every single line out of his mouth is solid comedic gold.
- Alfred Bester is one of the show's best-remembered characters, partly because he's fucking Walter Koenig, but also because he is absolutely nothing like Chekov. A nasty piece of work, for sure, but so, so very smooth.
- Narn gladiator turned bodyguard and (in the final episodes) Ambadassador Ta'Lon only makes five appearances, but is constantly praised as a compelling character with a lot of potential.
- Aldous Gajic from "Grail" is easily one of the most iconic and beloved guest stars of season 1 due to being a Too Good for This Sinful Earth Seeker Archetype and Martial Pacifist played by David Warner.
- Psi Corps military liaison Harriman Gray (Jeffrey Combs) is only in one episode and one non-canon novel, but his Reasonable Authority Figure moments and Tragic Dream of being a fighter pilot make him, for some, the best-liked member of his faction besides Bester.
- Elric the technomage only appears in one episode and a few books, but is beloved for his defiant contempt for those who seek to abuse the status and power of his people, and his The Trickster moments as he uses sorcery to punish said people.
- Shell-Shocked Veteran and Harbinger of Impending Doom Amis is only in one episode, but his Large Ham introduction, nuanced and touching friendship with Garibaldi, and battle against a servant of the Shadows make him a very well-remembered guest star.
- Centauri Emperor Turhan makes the most of his characterization as The Atoner and a believer in Modest Royalty once he finally becomes Unseen No More makes many lament how one of the best faction leaders in the series only gets a single episode.
- Four-Star Badass General Richard Franklin and Garibaldi's ladette Girl of the Week Dodger from "GROPOS" make a powerful and lasting impression in their guest roles, especially Dodger, who dies in her introductory episode but still comes back as a ghost in one season 5 episode.*
- Snarky, insightful, and occasionally, bombastic Baptist minister and Rebel spy Will Dexter is only in one episode, but provides some very memorable scenes.
- No less than three characters who only appear in "Severed Dreams" (with maybe ten minutes of screen time between them) all have a special place in the heart of the fandom.
- Major Ryan, for being a contemplative Bearer of Bad News Hero of Another Story who helps push Sheridan into some game-changing actions, sadly reflects on What Measure Is a Mook?, and is played by Bruce McGill.
- Captain Sandra Hiroshi and her Lady of War moments are well-remembered enough that an image of her is used as a placeholder for not just her episode but the entire series on the Roku streaming service.
- Intrepid Reporter Rick, who denounces President Clark as his troops raid the news building to enact their censorship.
- David "King Arthur" McIntyre, the Shell-Shocked Veteran who lived through the Battle of the Line and much more during the Minbari War and goes on to be a delusional but accomplished and spiritual Knight Errant who eventually leaves to use his knightly methods to help the Narn Resistance.
- Dr. Mary Kirkish only appears in two scenes of one episode, but her powerful Mr. Exposition moment and Adventurer Archaeologist Back Story seared her into many fans' memories.
- Captain Ericsson is an absolute scene stealer in maybe three minutes of screentime due to being played by Bryan Cranston and the stoic way he accepts the responsibility of a vital Suicide Mission.
- Bo and Mack from "A View from the Gallery" are generally agreed to be guest stars who do a good job holding the spotlight in the show's Lower-Deck Episode.
