Team Lightyear

Captain Buzz Lightyear (Tim Allen in The Adventure Begins, Patrick Warburton in the actual series): Famed "Space Ranger" known for heroism and bravery. Like his Toy Story incarnation, Buzz is a stickler for procedure. He attended PS -19^3 (that's 6859) as a primary school.
Princess Mira Nova (Nicole Sullivan): A rookie ranger and heir to the Tangean throne. She utilizes her people's ability to walk through walls (called "ghosting") and read minds. Buzz has a tendency to refer to her as "Princess" when he's angry with her.
Booster Sinclair Munchapper (Stephen Furst): A huge dinosaur-like former janitor from the agricultural planet of Jo-ad (a play on the name of the Joad family, from John Steinbeck's The Grapes of Wrath), with a big appetite and lots of muscle power. He is in awe of Buzz Lightyear.
XR (Larry Miller and Neil Flynn): A short robot with many pop-out gadgets (like R2-D2), who can store objects in his chest cavity (like Bender). XR stands for experimental ranger (The LGMs have stated that this is the official meaning of the name, though other characters on the show hold the erroneous belief that the X stands for expendable). He gets blown apart on nearly every mission he goes on, but is easily rebuilt.

Other Personnel
Commander Nebula (Adam Carolla): The Space Rangers' commander, whose left leg was replaced by a pegleg-like plasma cannon. Rather short-tempered and constantly speaks with a loud voice. Hates to do paperwork and therefore signs petitions without looking at them; by doing so, he inadvertently gave permission for the creation of XR, who therefore considers him a father.
Ty Parsec (Steve Hytner): Ty is the infamous old comrade of Buzz Lightyear. The Space Ranger was transformed into the robotic Wirewolf on the planet of Canis Lunis, after being bitten by the villain, NOS-4-A2. Appeared in two episodes, with a cameo appearance in the episode War, Peace, and War.
Rocket Crocket (Phil LaMarr): Member of Star Command and leader of Team Rocket (not to be confused with the Team Rocket from Pokémon). He is Buzz's rival since their academy days.
LGMs, or Little Green Men (Patrick Warburton): The LGMs are small, three-eyed aliens who keep Star Command in shape (originally appeared as squeeze toy aliens in Toy Story).
Petra Hammerhold (Nikki Cox): Senator Hammerhold's daughter. She joined Star Command when her father forced her to do so. Her boyfriend is Plasma Boy.
Plasma Boy (Michael Showalter): Petra's boyfriend, who has a Plasma Monster form. Booster competed against him for Petra's affection. When Mira and XR fired a laser at his Plasma Monster form, he destabilized enough to the brink of explosion. He was prevented from explosion when Booster used his suit and Ion Stablization Matrix on him. He's now a member of Star Command.
42 (Joy Behar): Usually the name of Buzz Lightyear's ship, it gained A.I. from one of the encounters with the Valkyran Raiders and a new energy projector device inserted on the ship by the LGMs. 42 doesn't like what Buzz says about her and usually controls the ship herself. XR developed a crush on her. When the Valkyran Raiders were thwarted, 42's consciousness was placed into a robot body and she now helps the LGMs.

The Villains
Evil Emperor Zurg (Wayne Knight): Main villain of the series. Rules an evil empire on Planet Z, and wants to rule the entire galaxy. Most of his subjects are robots. His feet double as rockets and he can transform his arms into a variety of weapons. Despite often breaking the seriousness of otherwise purely evil statements, Zurg is widely considered the most evil person in the galaxy, especially by the other villains. He seems to have some neuroses about being touched. In some episodes is shown being comical.
Lord Angstrom (David Warner): Lord of Tangea, former royal Chancellor and King Nova's closest adviser, before he worked with the Tangean Grounders to overthrow King Nova.
Brain Pods (Various Voices for each one): Cybernetic brains in mobile jars who serve Zurg as scientists and researchers. Although they take pride in their creations, they secretly harbor a desire to escape from Zurg's control (which two have succeeded in doing).
Care-Bots (Wallace Langham): Robot butlers built by the owners of an incredibly large spaceship. They are the embodiment of the term, "neat-freak", as they believe that cleanliness is alpha priority. This led to disaster, as they believed that organic beings (and XR) caused disorder, and for the sake of their pristine spaceship they attempted to "take care of" every living being (and XR) on the ship using hi-tech freeze rays, including the pilots. This nearly caused their massive shuttle to crash into Capital Planet's sun, causing a supernova, and causing an entire galaxy to perish. They were last seen drifting in space.
Chlorm Scientists: Era (Jonathan Harris), Eon (Bill Mumy), and Epoch (Frank Welker) are Chlorm scientists who implanted devices into Buzz and Warp Darkmatter to study good and evil. Buzz and Warp thwarted them. They later kidnapped Galactic Alliance senators for their zoos, as they see the other races as wild animals. Team Lightyear thwarts this plan.
Crumford Lorak (Jon Favreau): Resident of Trade World who is a known scam artist and a stool pigeon for Star Command if the price is right. Crumford is in fact one of the Space Rangers best and worst assets when it came to gathering info on major bad guys. The only time when Lumford went big-time was when he impersonated Senator Banda of Bathyos in order to give information of the Galactic Alliance to the Raenok leader, Varg.
Evil Buzz Lightyear (Patrick Warburton): A ruthless, pure evil version of Buzz Lightyear from an alternate reality which he conquered. He was his reality's ruler, head of a vast evil empire, and was very cruel and cunning, manipulating Zurg and Gravitina (who adored him) to his own wicked ends. He is the exact opposite of Buzz in personality and demeanor, wears a modified uniform in colors similar to Zurg's, and has a goatee (a reference to Star Trek, where evil doubles tend to sport that hairstyle). However, he can survive things like Buzz that most people can't, such as surviving his ship's own explosion or falling into the sun.
Flint (Mark Hamill): An android stockboy who got tired of his forced labor and planned revenge. He created manta ray-like shriekers to attack ships resulting in castaways on the planet his shriekers were built. He portrayed himself to be the leader of the village where the castaways resided until he was exposed and defeated by Team Lightyear.
Gargantian Militants: Tiny beings who hide in robotic exosuits. They use these suits as various disguises/ways to infiltrate what they desire. The Gargantian Militants hate commercial places on their planets as well as the fact that their people joined the Galactic Alliance, meaning no wars. They are led by Tremendor (Kevin Michael Richardson). Another known Gargantian Militant is Monumentus (Charles Fleischer) whom is Tremendor's second-in-command. Immensitor and Behemor (both also voiced by Kevin Michael Richardson) are also members of the Gargantian Militants. As a joke, most Gargantian names, as well as species as a whole, are an ironic pun to their small stature
Gravitina (Kerri Kenney-Silver): A large-headed female villain with mental control over gravity. One of Zurg's allies. Is in love with Buzz and later his evil counterpart.
Grubs (Frank Welker): Zurg's equivalents to the LGMs of Star Command (though far less competent). They perform more mechanical and technical duties than the Brain Pods. Like them, the Grubs work for Zurg against their will, and also desire freedom.
Minister Gularis (Harvey Korman): A shark-like Bathyosian minister and leader of the Bathyosian Council who is secretly head of the B.A.R.R. (Bathyosians Against Air-Breathers) movement. He wears a device with mechanical arms on him. He planned to use a Tritum Missile that would turn any planet's atmosphere to match Bathyos, in short, create a new water world. It took Buzz Lightyear and Officer Panchex to thwart his plans.
The Heed: A race of supposedly semi-omnipetent beings who in fact have an ulterior motive, that of conquering the galaxy (Much Like Star Trek: The Next Generation's Borg). A Heed named Guzelian (Eric Idle) used the Grubs and the LGM's to trick the galaxy into believing that he was spreading Galactic Peace. Once both sides had disable their weapons, the Heed would take the opportunity to strike. However Buzz and Zurg team up to stop them by broadcasting his confession all across the galaxy. They then fled as both Star Command and Zurg's empire rearmed themselves.
Hornets: The Hornets are Zurg's robotic foot soldiers, extremely expendable (similar to battle droids from Star Wars), lousy shots, and always get vaporized in mass numbers by Lightyear's team. Hornets come in different models outside of the lesser models used.
Keno Kentrix (Jess Harnell): A Bathyosian casino owner on Mahambas 6 who was behind the weapons smuggling. When XR heads into Keno's casino disguised as Booster (since robots aren't allowed in his casino) and makes a pass at Keno's girl, Keno place a bounty on Booster's head. When XR admits to Keno, he and the bounty hunters attack until they are thwarted by Buzz and Keno is arrested.
Lardak Lurdak (Kevin Michael Richardson): A minor criminal in a dome helmet.
Natron (Diedrich Bader): An ancient evil space mummy. In his time, he ruled the universe as an ultimate "invincible" evil. Defeated and imprisoned by "The Protector," he vowed to once again rule the universe, and is awakened by the LGMs on Planet X thousands of years later. He took Warp's life force and began to use his technology to attack and freeze everyone on Capital Planet. He was stopped when the LGMs returned the stolen life force to warp and was imprisoned again. Buzz tested if he could break out again by vaporizing the door into sand. His name is based on natrium (salt) used in mummification.
Norbert Q. Klerm (Mitchell Whitfield): The rich and ruthless head of the business company "Compu-klerm." He is friends with the Madame President. He first appeared to make Buzz Lightyear and Zurg fight each other. He later brainwashed Buzz into thinking he was a Compu-klerm employee named "Flip Faxtoner", and occasionally picked Buzz's brain with a large helmet for combat data to use in his battle robots. His plans were ultimately thwarted by Buzz when he came to his senses and replaced his bots' brains with a fellow co-worker.
NOS-4-A2 (Craig Ferguson): NOS-4-A2 is a robotic vampire created by Zurg, capable of draining any system or entity driven by electrical power, and controlling any machine he bites. His bite also seems to have some effect on organics, because he is the one who is responsible for biting Ty Parsec, resulting in the Space Ranger turning into Wirewolf. His name is a pun on the term Nosferatu.
Raenoks: The Raenoks are the fiercest aliens in the Galaxy. Varg (Kevin Michael Richardson) is the ambassador of the Raenoks and the supreme commander of the Raenok military. Kleev (Clancy Brown) is the leader of the Raenoks and Minister of Schemes and Treachery.
Professor Spyro Von Madman (Ryan Stiles): Spyro Lepton is a former Star Command scientist whose banned experiments lead to his transformation into a Cryborg, a being with a crystalline basis. He gets powerful by feeding off electricity. After years of plotting revenge on Buzz Lightyear and a messy rampage on Capital Planet, he was restored to normal by his daughter Bonnie Lepton (Tara Strong). He has supposedly reformed.
Rentwhistle Swack (French Stewart): A con man who was first seen poaching creatures on Karn. Booster arrested him once prior to this event. He later was Norbert Q. Klerm's "agent/booker/tour guide" when Norbert was making Buzz and Zurg fight each other.
Roswellean Major (Peter MacNicol): A member of Planet Roswell's military who captured Team Lightyear hoping to dissect them. After they got away, he was demoted to Private by his General. He later sided with Zurg in his domination of Roswell which is thwarted by Buzz and Booster and was arrested for collaborating. Roswellians are based on how aliens were described at the time of the Roswell Incident.
Shiv Katall (Patrick Warburton): A mysterious soldier of fortune/mercenary/hitman/bounty hunter usually hired by Zurg to eliminate Brain Pods and Grubs who get up enough guts to defect from Zurg. He is secretly a covert identity adopted by Buzz Lightyear, and before Buzz, Commander Nebula. Unfortunately, that identity was compromised due to the actions of Mira, Booster and XR. At the end of said episode it was hinted that Booster was going to become the next Shiv Katall, but it was ignored in future episodes. In a later episode the evil Buzz Lightyear used the Shiv Katall guise in order to acquire parts for a base station he was building near Capital Planet's sun, in order for him and Gravitina to use it to produce 'sunquakes', threatening all nearby life.
Smeego (Phil LaMarr): A fidgety small time crook and acquaintance of Torque. He can sometimes be found on Trade World.
Smoltz (Wallace Langham): He's from the same alien race as the Madame President. He was a turn-coat working for Zurg when the Madame President's transport crashed on Karn. When Zurg and his Hornets drove away some Karnian creatures, he revealed his true intentions and the reason why Mira Nova was picked for that mission. When Team Lightyear rescue Mira and the Madame President, Smoltz and Zurg pursued them before being chased away by a mother Narlzak and her young.
Tangean Grounders: Ground-dwellers of Tangea. They can explode things with their minds. Grounder Clay (Jess Harnell) and Grounder Marl (John Kassir) are examples of Grounders that live on Tangea. A Tangean Grounder and bounty hunter named Romac (David James Elliott), who was Mira's ex-boyfriend, was hired by Zurg to obtain Brain Pod #57. Grounders and Tangeans lose their respective super-abilities when close to each other.
Team Lightyear Clones: Created by Zurg to thwart the real Team Lightyear. However, due to Zurg's impatience, they were child versions of the originals. Their distilled evil was 12, one point short of Zurg's 13. Wanting to have a robot similar to XR, the children create X-Treme. They were defeated when the team used their most greatest weaknesses against them. X-Treme was defeated by a magnet. Zurg had them put in their chambers again but they emerged out too old.
Zzub (Cloned from Buzz) (Patrick Warburton):
Feara (Cloned from Mira) (Nicole Sullivan):
Blister (Cloned from Booster) (Stephen Furst):
X-Treme (Modeled after XR) (Neil Flynn):
Torque (Brad Garrett): Minor alien villain who committed crimes of terrorism, smuggling, arson, and unpaid parking tickets. After being freed from a prison transport by Zurg and his Hornets, the Grubs implanted a cell-separation device upon his chest which allows Torque to have the ability to create duplicate versions of himself. In "The Taking of PC-7," he tried to turn Booster evil (and later Buzz) with a memory-altering device built by the Warden of PC-7.
Valkyran Raiders: Brun, Sig, and Hilda (all three are voiced by Tress MacNeille) are female space pirates who attack freighters in search of cargo to use for trade and personal use. The mothership of the Valkyran Raiders uses a cloaking device.
Vartkes (Ricardo Montalbán): 20 Years Ago, a temporary-resigned Buzz Lightyear confronted this villain. Vartkes is a gas baron who tried to take over a cloud farm owned by a woman named Zoey. He tried to get her to sell her farm. When Zoey tried to take him on, Vartkes surrounded them with his robots until Buzz arrived. With a Puffer named Little Joe, he was able to take down Vartkes and his goons.
Warp Darkmatter (Diedrich Bader): Buzz's one time partner, but now a recurring villain under the codename "Agent Z." Lost his right arm after being buried in an avalanche by Zurg on a routine mission with Buzz, now works as a mercenary in Zurg's employ.
Wirewolf: Formerly Space Ranger Ty Parsec. After being bitten by NOS-4-A2, the radiation of Canis Lunus's Green Moon turns him into a robotic lupine, who, like his creator, feeds on energy.
XL (Bobcat Goldthwait): Earlier version of XR, which was shut down due to his villainous attitude. When he was reactivated by Zurg, XL became larger and more powerful due to his rebuilding himself with stolen robot parts. Also has a red (As opposed to XR's yellow) head. He infiltrates Star Command numerous time because its command codes are in his head. He later redeems himself and reconciliates with XR (his "younger brother") and is converted into an office managing robot capable of photocopying, collating, and other office related functions. Both XR and XL refer to the commander as "Dad" and after XL's conversion, the two of them annoy him to no ends with their ideas for family activities. His name is a pun referring to his size (extra large)

Galactic Alliance
Madam President (Roz Ryan): Head of the Galactic Alliance. Her real name is unknown.
Senator Aarrfvox (Jim Cummings): A Shragorakian senator.
Senator Banda (Dan Castellaneta): A Bathyosian senator.
Senator Hammerhold (Corey Burton): Petra Hammerhold's father.
Senator Phlegmex (Frank Welker): A slime-emitting senator.

Other Characters
Becky (Russi Taylor): A little alien girl from the planet Roswell. She befriended Booster (who she calls Pickles) when Team Lightyear's ship crashed on her planet. Her father is the Sheriff (Stephen Root) of her town.
Brent Starkisser (Corey Burton): The Galaxy's reporter.
Cosmo (Paul Rugg): An alien that owns and runs the diner that Team Lightyear eats at. He has a mechanical arm as well as a foreign accent.
Dr. Animus (Tony Jay): The Galaxy's therapist.
Dr. Ozma Furbanna (Linda Hamilton): Lead (and only) naturalist on planet Karn. She favors all animals (even the lethal carnivores) and hates to have them hurt; no matter what. Has a crush on Buzz (won't admit it, though), and vice-versa. Zurg once used her help to hatch the Millennial (entirely ticklish) Bugs where Zurg will use them on Capital Planet.
Ed (Paul Rugg): A courier who somehow always knows how to track down Buzz Lightyear.
Professor Triffid (Joel Murray): A scientist from Rhizome. He cares a lot for the plants there.