As a high P12, Byron (surname is "Gordon" according to the novel Deadly Relations) used to be a Psi Cop, a protégé of Bester's - until his part in the murder of a ship full of mundanes caused him to rebel (Phoenix Rising, Deadly Relations).  He became leader and representative of a group of rogue telepaths who sought sanctuary on Babylon 5 in 2262 (No Compromise), in return for providing Sheridan with their services to the Interstellar Alliance (The Paragon of Animals).  As he evolved into the single most boring and annoying character ever to appear on Babylon 5, he developed a relationship with Lyta Alexander as she worked to help and protect the telepaths (Strange Relations), and from her knowledge of the Vorlon/Shadow influence in creating telepaths, he decides that their time as mere tools are over and demands a home planet of their very own (In the Kingdom of the Blind).   He becomes upset when the telepaths begin to use his name in vain in battling with the mundanes (The Tragedy of Telepaths) and decides to sacrifice his life to prevent further bloodshed (Phoenix Rising).

Played by Robin Atken Downes, who played the Minbari Morann in Atonement and the telemovie In the Beginning.  He has also appeared in Buffy: The Vampire Slayer, Charmed, and Beverly Hills 90210, and composed the music for the 1997 movie Tunnel Rat.

First seen in Signs and Portents, this C&C staff officer wasn't actually named until And Now For a Word.   Shortly after his promotion from Second Lieutenant to Lieutenant (Junior Grade), Ivanova tested his loyalty in Exogenesis to determine whether or not he would betray them in their opposition to President Clark's orders.

Played by Joshua Cox.

Businessman residing on Mars who married Garibaldi's old girlfriend, Lise Hampton.  He employed Garibaldi (Racing Mars) after he resigned from his position as Chief of Security on Babylon 5 to help him smuggle certain substances past customs (Conflicts of Interest, Moments of Transition).  He intended to use Garibaldi to capture Sheridan before he could disrupt his own plans to remove Clark, as well as develop a virus that would prevent telepaths from becoming an elite ruling class.  He was killed by Psi Corps when they discovered his plan (The Exercise of Vital Powers, The Face of the Enemy).

Played by Efram Zimbalist Jr. who appeared in the Maverick TV series and the movie Hot Shots!, among others.  He also provided the voice of Alfred the Butler in some of the Batman: The Animated Series episodes.

Commanding officer of the Alexander and Sheridan's Earthforce liaison (Points of Departure), eventually becoming a contact for the covert movement to expose President Clark (All Alone in the Night, Hunter, Prey).  He was killed in battle after Clark issued the order for Martial Law (Severed Dreams).

Played by Robert Foxworth, who appeared as Admiral Leyton in the Star Trek: Deep Space Nine episodes Homefront and Paradise Lost.

Leader of the resistance movement on Mars with whom Dr Stephen Franklin successfully managed to get off with (Racing Mars, Lines of Communication, The Face of the Enemy, Between the Darkness and the Light, Endgame).  After President Clark was deposed, she became a member of independent Mars' provisional government, and eventually the new head of Intergalactic Alliance security (Objects in Motion), working from Babylon 5 (Objects at Rest).

Played by Marjorie Monahan, who appeared in the sci-fi series Space Rangers.

Michael Garibaldi's former girlfriend who remained on Mars after he left for Babylon 5 (Babylon Squared), and married a man named "Franz" (A Voice in the Wilderness, Part II).  After divorcing him, she married businessman William Edgars six months before meeting up with Garibaldi again, when Edgars employed his services (Conflicts of Interest, The Exercise of Vital Powers). She escaped capture by Psi Corps when they killed her husband (The Face of the Enemy) and went on the run before being located by Garibaldi (Rising Star).  When he failed to follow up his promise to return to Mars, she returned to Babylon 5 looking for him (Darkness Ascending).  She eventually marries him (Wheel of Fire, Objects in Motion) and together they manage Edgars-Garibaldi Industries, eventually having a daughter, Mary.

Played by Denise Gentile, who has appeared in the TV shows Quantum Leap and The Drew Carey Show and the film Netherworld.

EarthGov Senator, and Sinclair's liaison (Deathwalker, By Any Means Necessary, A Voice in the Wilderness, Part II) who was removed from office after Clark's ascension to Presidency (And Now For a Word).  (He also makes an appearance in the comic The Price of Peace and the novel Voices.)

Played by Aki Aleong, who played Mr Chaing in the TV series V, and has also appeared in The A Team, SeaQuest DSV, and Seven Days. 

Expert Starfury pilot who, after encountering a Shadow ship in hyperspace (A Distant Star), became obsessed with investigating it - even at the cost of his own life (The Fall of Night).

Played by Robert Rusler, who appeared in the film Nightmare on Elm Street 2: Freddy's Revenge.

First Medical Officer assigned to Babylon 5 in 2257 (The Gathering), but after he saw inside Kosh's encounter suit he was quickly recalled to Earth (as mentioned in The War Prayer).  He decided to retire from medicine in 2262, nominating Dr Stephen Franklin as his replacement (The Ragged Edge).

Played by Johnny Sekka.

Former girlfriend of Jeffrey Sinclair who returned to Babylon 5 and was reunited with him (The Parliament of Dreams, Mind War). Sinclair finally asked her to marry him shortly before he was transferred off Babylon 5, and sent to Minbar (Chrysalis).  After returning from a survey mission on the galactic rim, she joined the Rangers to be with Sinclair - and shortly after her graduation, was sent on a mission to prevent Shadow activity in Sector 14 (Babylon Squared) - where she disappeared into the time rift (see the novel To Dream in the City of Sorrows). Garibaldi mentions her disappearance in Darkness Ascending.

Played by Julia Nickson-Soul (credited as Julia Nickson), who appeared in Star Trek: The Next Generation, Star Trek: Deep Space Nine, the miniseries of Around the World in 80 Days with Pierce Brosnan, and the film Rambo: First Blood Part 2.

Re-elected President of the Earth Alliance in early 2258 (Midnight on the Firing Line), paid a quick visit to Babylon 5 in the middle of the same year (Survivors, although he wasn't seen on screen), and was killed when Earthforce One exploded at the transfer point on Io at the end of the year (Chrysalis).  His policies were of a nature intending humans to co-operate peacefully with their neighbours, with which Vice President Clark, who succeeded him as President, did not agree (Voices of Authority).

Although the character does not actually appear in person, a photo posed by series co-Executive Producer Douglas Netter is seen instead.

Late wife of Captain John Sheridan and long-time friend of his sister, Elizabeth.  She was a researcher with Interplanetary Expeditions and was aboard the Icarus on its doomed mission to Z'ha'dum (Revelations, In the Shadow of Z'ha'dum, and the novel The Shadow Within).  She is one of at least two survivors from the mission (alongside Morden), at first serving as a pilot of a Shadow vessel (The Passing of the Techno-mages), and then acting to lure John Sheridan to Z'ha'dum (Shadow Dancing, Z'ha'dum).  Presumably she died in the explosion Sheridan triggered.

First played by Beth Toussaint (Revelations) who played Ishara Yar, Tasha Yar's sister in the Star Trek: The Next Generation episode Legacy.

Later played by Bruce Boxleitner's wife Melissa Gilbert (Z'ha'dum), who appeared in the TV series Little House on the Prairie.

Father of John Sheridan and former diplomat.  He used to take his family out for a drive every Sunday (Sleeping in Light), and gave John a sound piece of advice: "Never start a fight, but always finish it" (Severed Dreams, Objects at Rest).  Kosh appeared as an image of David Sheridan to John when he was being attacked by the Shadows (Interludes and Examinations).  He disappeared when his home town was stormed by Earthforce soldiers (The Illusion of Truth), but Garibaldi tracked him down by the Centauri drug he requires to treat his rare blood condition (The Exercise of Vital Powers, The Face of the Enemy).   He was reunited with his son after Earth was saved from President Clark (Rising Star).

Played by Rance Howard, father of Happy Days star and film director Ron Howard.

Takashima was stationed on Mars under Commander Jeffrey Sinclair, just prior to the food riots.  She was assigned to First Officer on Babylon 5 when it went online, however she did not remain long (The Gathering).

Had the character remained, it would have been she who shot Garibaldi (Chrysalis) and revealed to have a secondary personality implanted by Psi Corps (Divided Loyalties).

Played by Tamlyn Tomita.

Leader of a group of monks who took up residence on Babylon 5 (Convictions, Passing Through Gethsemane, And the Rock Cried Out, No Hiding Place).

Played by Louis Turenne, who originally played Draal in A Voice in the Wilderness but was unable to reprise that role after suffering a stroke.