Dr. Roberto Martinez ? A technical genius in his late teen years, 'Berto (his nickname) is the main expert on Nano-Tek Max, the microscopic machines which gave Josh his superhuman abilities. 'Berto is usually based at the HQ of the secret intelligence service N-Tek where he monitors Max's missions via a computer screen, but he also often takes a more active part in the missions himself. He has family in Colombia, although how many relatives is unknown. From the moment they met, he and Josh became very close: Josh would call Roberto "Bro", who would respond with the Spanish version "Hermano". Voiced by Jacob Vargas.

Rachel Leeds ? Max's first partner at N-Tek. Although her country of origin is not specified, her English accent indicates that she may be a British national, one of several non-Americans who work at N-Tek. N-Tek answers to the UN and includes a number of other non-US citizens on its staff, such as Jean Mairot and Roberto Martinez. Rachel has a rather bossy personality but is very attractive in her own way. Much of season 1 focused on her relationship with Max: from one of constant squabbling to increasing attraction on his part, which affected Josh's relationship with his girlfriend Laura Chen. At one stage Rachel did kiss Max as a way of calming him down when he was getting particularly agitated, but seemed to think that he ought to stick to Laura: one episode concludes with Rachel smiling and saying "Blessings on your union" in Chinese as Josh and Laura leave arm-in-arm. After the second series, Rachel was promoted and disappeared after three episodes. There is speculation that she has a brief, non-speaking appearance in season two, episode four, but it is also likely that it was just a reused model. Voiced by Shannon Kenny.

Kat Ryan ? After Rachel's promotion in season two, Kat, another of her prot?g?s, became Max's new partner. At first they didn't get along, but, after Jefferson Smith forced them to work together, they developed a little mutual respect. About the same age as Josh and Roberto, her relationship with the two boys is like that of a sister, much like they see each other as brothers. Kat was never given a surname until season three, and it was revealed in the second-to-last episode that, when she was younger, she was part of a street gang. Voiced by Debi Mae West.

Laura Chen and Pete Costas ? Two of Josh's college friends, Pete referring to themselves as "the Three Musketeers" given that they used to be very close, until Josh's life as Max Steel started to interfere. Laura Chen was Josh's girlfriend but she soon broke up with him due in part to his increasingly close relationship with Rachel Leeds. He also kept his activities as Max Steel a secret from her and this would affect dates and other commitments which made him somewhat unreliable. Pete, in the season two premiere, found out about Josh's dual identity after being captured by John Dread and agreed to keep it secret. He was not seen in season 3.

Jefferson Smith ? The CEO of N-Tek, both the sports and spy sides. He inherited this position from Marco Nathanson, the previous and first CEO of N-Tek. He is the adopted father of Josh McGrath after his mother, Molly, and father, Jim, both died. Jefferson might be based on "Big Jeff" from Mattel's 1970's Big Jim toy line, though Jeff was white, while it was "Big Jack" who was the main African-American character. Voiced by Chi McBride

Jean Mairot ? Smith's second-in-command at N-Tek in season one and head of operations, briefing agents on their missions and co-ordinating their progress. A soft-spoken man, he is cool and calculating and a good judge of character ? putting Max in charge of a major rescue operation even though the boy himself did not feel up to it. At the end of season one, Mairot turned out to be a spy working for villain John Dread. His fate in unknown, though it is presumed that he was caught in the explosion of Dread's base. His treachery was a bitter blow to the N-Tek staff, all of whom had liked Jean. Mairot spoke in a French accent, voiced by Keith Szarabajka

Charles Marshack ? An N-Tek division chief who's in charge of Behemoth, the massive flying fortress used as a mobile base to support Max. He's a senior, probably around 60 years old, who assists N-Tek with his expertise. He was a close friend of Big Jim and acts a bit fatherly with Max. Despite his age and butler-like appearance, he can move extremely fast, and is an experienced hand to hand combatant.

Jake Nez ? N-Tek agent and astronaut, formerly from NASA. He was also once a love interest of Rachel's but was dumped by her when she started training Max.

Rocket ? A wounded hawk rescued by Max in Endangered Species. Due to the extension of his injuries, 'Berto reconstructed him using N-Tek technology. Now he has a bionic leg and a cybernetic eye which has a camera with recorder, night vision and zoom. What Rocket can see, can be transmitted to other N-Tek members. The hawk it is supposed to be a companion for Max, but most of the time it is in 'Berto's custody.

DREAD/Other organizations and enemies

John Dread ? the leader of the DREAD organization, and the main antagonist of the early series. He's rarely seen outside of offices and rooms in dark secluded buildings, and only made two known appearances where he was the main or part of a main threat. There is fandom speculation that John Dread and Marco Nathanson (the N-Tek founder) are the same person, although this has been debunked by Greg Weisman, the story editor of the first season. Voiced by Martin Jarvis (actor).

L'Etranger ? "The Stranger", as his name translates from French into English. He wears a mask over his face, which appears to resemble a skull, with no facial details, and was the first villain Max fought against in the TV show. At the end of that episode Dread mentions that he is not a full-time member of his organization. By the time of his second appearance, he is said to no longer work for Dread. He is a mercenary terrorist armed with electrical charged gloves which can produce an explosive spark. Being an electrical weapon, one hit is more than enough to stun for a large period of time his enemies.

Psycho ? His real name is unknown, although his nickname/DREAD code-name is speculated to come from the fact that he appears to be a psychopath. He's often called "Smiley", mainly by Max but occasionally by other members of N-Tek. Usually he doesn't care about it, but for some reason has very violent reactions when other members of DREAD addresses him with that nickname. He has a metallic face which looks like a human skull, with an unusually large smiling jaw (hence the reason of his nickname), which most of the time is covered up using a mask which gives him the appearance of a normal though white guy. His main weapon is his right bionic arm, which can change into a claw or a laser gun, presumably by nerve signals. The action figures of Psycho also included bazookas, missile launchers, grappling hooks, chainsaws and many other gadgets for his bionic arm, but this accessories never appeared in the TV show. Psycho also has an army of Psycho-bots, which looks almost like him, except they are silver or copper colored. None of the androids has an armed bionic arm as Psycho does and they are notoriously more fragile. Voiced by Keith Szarabajka

Dragonelle ? She is the first major female villain shown. The origins of her code-name is unclear, although there is speculation that she comes from China (as that is where the episode which she appeared in for the first time took place). As dragons are a key part of Chinese mythology, it is believed that she took this name for good luck. She's dressed in a golden battle armor, but always runs away from any physical confrontation, since she's more an undercover agent than an active fighter. She has the ability to mimic the actions and appearance of any person she has seen and impersonate them perfectly. Voiced by Mia Korf.

Vitriol ? According to Max, "not the brightest tool in the shed" which explains why he often teams along with Psycho. While they are supposed to be equal members of DREAD, Vitriol usually follows Psycho's orders. His arms are vibrant, translucent green with simple metallic 'bones' visible, and can shoot green energy beams, which can be very destructive. At the end of season one, he realizes he's an expendable pawn, and decides to quit DREAD and cooperate with N-Tek.

Woody and Annabelle Barkowski ? Two siblings who are intent on bringing down N-Tek: Woody because he believes that they gave him a faulty mountain bike to cause him to break his leg and thus retire from the extreme sports world. Woody considers himself to be Max Steel's arch-nemesis, but Max mentions that he "barely qualifies as comic relief." Annabelle collaborates with her brother in the first season and seeks revenge for her brother in the second season. In series two, Annabelle suffers an accident in her laboratory and her body is never found. It is later revealed that Annabelle's body using electrical currents and sources as an energy supply, much like how the nanoprobes in Max's body uses transphasic energy.

Bio-Constrictor ? His full name is "Biologically Altered Constricting Serpent", having been given this name by 'Berto. He is usually addressed as "Bio-Con" in the series and movies, but in the toy's packages is named Bio-constrictor instead. Dr. Klimo was involved in an accident what is thought to be injected with electrified snake venom, and thus mutated into a half-human, half reptile with the abilities to turn into a snake, poison people with highly-toxic venom or use his venom to transform other people into copies of his mutated self. Bio-Con looks more like a leather mummy than a snake, mostly because his body is composed of several serpents twisted around what seems to be his base skeleton. Before his accident, he was an employee fired for erratic behavior, mainly due to the use of turning poisonous animals, such as scorpions and snakes, into biological weapons, which appears to form a basis of the plotline of the Endangered Species movie. He initially meet Josh when he was younger, and they used to play baseball together. He was voiced by Rene Auberjonois, who also played the equally bad-tempered, shape-shifting Odo in Star Trek: Deep Space Nine.

Elementor ? Probably the most versatile of all Max's enemies, Elementor originally started as a Bio-Con clone who went mad. The reptile like creature enhances his natural abilities with the use of different isotopes which grants him the capacity to mimic different basic elements. Elementor can transform himself into a mass of rock(earth), water, air, lava (fire) or metal, and adopts the natural physics of those materials. Being a clone of Bio-Con, Elementor remembers everything Dr. Klimo knew up to the date of his creation. Despite having the memori
es of a scientist, Elementor does not shows any talent for science. He prefers the pure brute force approach.

Warren Hunter ? And old friend and partner of Jefferson Smith. Long ago, their different points of view forced a business separation. While Jefferson was worried about the technology uses for betterment of mankind, Hunter was mostly worried about profits. Hunter is now the founder and CEO of Eclipse, a high tech development company which rivals N-Tek.

Iago ? In his initial presentation, it is a character so insignificant that nobody noticed his constant presence flying around, but later plays a major role as a double agent. Iago can only be described as a "floating PALM device with a laser" who in his first appearance is Warren Hunter's assistant. Initially, he does mostly nothing except floating all over the place, but shows some potential as a weapon when takes custody of several hostages. In the movie Bio Crisis it is revealed that he has been secretly working for Dr. Grigor Rendel stealing technology and copying files from N-Tek and Eclipse. He helps in the construction of Cytro and has been powered up himself, using Warren and Rendel for his own purposes, posing as an innocent assistant. It is not clear if he really serves an unknown master or has an agenda on his own. Also it is unknown if "Iago" is the code name of the floating device or the program. In some scenes, several "Iagos" appears at the same time working as a team. Destroying one only causes the apparition of a new one to substitute the previous one. All shares the same voice and personality, and acts mostly as different drones sharing the same mind. However, in Bio Crisis movie, 'Berto arrests "him". The prisoner is exactly the same model as all other Iagos, with no difference at all.

Extroyer ? Troy Winter, a special agent and mercenary hired by Eclipse who can match Max's enhanced abilities without effort. Troy suffers a chemical mutation with a crystal fragment from Morphosos Comet which transforms him into a crystal like creature who can absorb other people's life force and identity, and in the particular case of super human entities, their respective powers. Once he absorbs a living being, he can reuse its appearance as needed. When in Extroyer form, the left half of his head is often missing, and the interior of his empty skull can be seen as a formation of crystals. Sometime he only has the right eye, but when he takes another person's identity his head is complete and the impersonation is perfect. However, when copying other creatures he still has half head only.

Dr. Grigor Rendel ? A twisted scientist who tries to found a way to synthesize Morphosos Comet's crystals to recreate their energy in his particular laboratory for his own twisted purposes. He has developed a gadget that can revert Elementor to his original state as a reptile clone, with no powers at all, and constructed several battle robots and advanced weapons. The doctor himself is not a major threat, but most of his inventions are lethal. He does not care about the secondary effects of his experiments, which can be extremely dangerous for the environment or animals.

Cytro ? This battle android is a mechanic version of Dr. Jekyll & Mister Hyde. Created by Doctor Grigor Rendel, Cytro's directives states he must destroy N-Tek, but from time to time, as a result of a major battle damage, his programming fails and sees Max Steel as a friend instead. A curious thing to note, no matter if he is evil or good, his voice and attitude are more of an attentive and reflexive butler than a berserk warrior. Cytro's robotic body is expendable, and he cannot really be destroyed as long as a backup of his programming exists. The program which contains his personality just needs to be inserted into a new cybernetic body. Cytro is not just a tool. He can learn and take decisions on his own, despite his programming, and eventually develops a strange sense of humor: makes a human-like pose and then questions the purposes and utility of such behavior, which he finds pretty much useless.