The parents of the immediate Wilkerson Family are Hal and Lois. Originally, there were four brothers. From oldest to youngest, they were Francis, Reese, Malcolm, and Dewey. In the fourth season finale episode Baby Part 2, a fifth son was introduced named Jamie. In the episode Graduation, Lois discovered she was pregnant with a sixth child. This child was never born in the episode so most information about it is unknown.
In the episode Hal's Birthday, Francis travels home (to celebrate his father's birthday) with an Alaskan girl named Piama, and reveals that they are married. It is implied in "Hal's Christmas Gift" that the popularity order with the brothers is: Francis, Dewey, Reese, Jamie, then Malcolm. Throughout many of the series' episodes, the family is shown to be extremely loathed and despised by their neighbors.
Because of Hal's recklessness and incompetence as a man, Lois is supreme head of the household.
With each new son, the family's life sunk lower and lower.
Because of Lois and Hal's extremely low level incomes, the family virtually can't afford any form of luxuries or even basic living essentials (such as air conditioning, refrigeration and washing machines). All the boys clothes are hand me downs or flea market bought. As such, Bills are always late and the family is miserably in constant debt.
The Welker Family is Lois' side of the family. A Candian family, with Ida Kenzel and Victor Welker as the parents. Ida and Victor never officially got married, but Ida did have children and Victor helped raise them. Ida then gave birth to two kids, Lois Welker and Susan Welker. But Victor was not their true father. A man name Radu Gogorsky, who was never seen in the show was the true father of Lois. Victor was so unfaithful and neglectful in the first years of their marriage, that he found love with another family. Victor would always leave Ida, saying he was going on a business trip, when he was really visiting The Welker Family. Ida and Radu then gave birth to Lois and Victor would occasionally return to raise the child, making Lois believe that he was her real father. They also went under the last name "Welker" as opposed to "Kenzel" or "Gogorsky". This information hasn't been dwelt upon enough to understand much about. Even Ida knows very little about this topic, not even knowing if Susan is the child of Victor or Radu, although, it's most likely that she isn't.
As for Victor's other family, Victor was actually nice to his other family and was the true biological father of that family. He was married to a woman named Sylvia and had children, one of which was a daughter named Roberta, who had two children. Jerome and Scott. Given that Victor was never legally married to Ida or didn't biologically give birth to either of their children, The Wilkerson Family is in no way related to The Welker family.
Lois married Hal Wilkerson and they went under the Wilkerson family name.
In the episode Flashback, the births of the eldest four Wilkerson boys were delved into as we see a flashback to when Hal and Lois had all four of their kids. Lois and Hal conceived Francis nine months before they got married. When Lois went into labor, she immediately arranged a wedding for herself and Hal. She was having labor pains throughout the entire wedding and refused to go to the hospital until after they were legally wed, in order to prevent him from being born out of wedlock.
Lois and Hal had already named Reese before he was born. While she was pregnant with him, he caused a lot of pain inside her womb, kicking and violently moving around. When Lois gave birth to him, she suffered a lot more pain than usual with him. She forced the baby out, hours before he was supposed to be born because she couldn't stand the pain anymore.
When Lois became pregnant with Malcolm, the family had to move out of the apartment and into their current house in the suburbs. While Lois was still pregnant, Reese was two years old and Hal tried teaching him a bunch of random information about things such as art, natural history, science, etc. This left no impression on Reese, but because Lois was present, during that time, all of that knowledge transferred to Malcolm, making him the genius he is today. Lois and Hal got into a fight, which led to him going for a drive, just before Lois went into labor. She couldn't get herself to the hospital on time because of Francis being a nuisance, and so by the time Hal got back, Lois had already given birth to Malcolm in their front lawn and he had missed the whole thing.
While pregnant with Dewey, Lois had him exposed to nuclear radiation from the microwave, while he was still in the womb. When Lois went into labor, Malcolm had made unstable chlorine gas in the house, which caused a noxious gas leak in the house and the family had to evacuate, during a rainstorm. The keys to the car were inside the house and so Lois had to give birth to him on the front lawn.
In the episode Grandma Sues, Lois found out that she was pregnant with Jamie, and gave birth to him in the episode Baby Part 2. When Lois went into labor, she was unable to leave the house because Hal had crahsed the car in a rushed attempt to get home. Because of this, Lois gave birth to Jamie in the guest bedroom.
In the episode Graduation, Lois found out that she was pregnant with yet another child, much to the terror of both her and Hal. However, this was their final appearance in the series, so nothing is known about who the child was or what happened when they gave birth to it, or even if they decided to keep it.
- Malcolm Wilkerson - He is the central character of the show. He starts the show at age 11 but by the end of the series he is 17 and graduated. He is shown to being extraordinarily intelligent with an IQ of 165 at age 11. In the first seasons of the show he is put into a class with the Krelboynes. He is the middle child and feels like he doesn't fit in with others. In the end it is revealed that his parents wanted him to have a hard life so that he would be successful throughout the rest of his life. Malcolm is played by Frankie Muniz.
- Reese Wilkerson - The second oldest of the family, Reese was always the head trouble-maker. He is great at cooking and baking, while he lacks intelligence. After a bad break-up he enlists in the military while underage and he has to repeat a grade when he fails all of his classes. He is much like the character PJ Duncan on the Disney show Good Luck Charlie except that PJ is the oldest child and PJ is kind to everyone. Reese is played by Justin Berfield.
- Dewey Wilkerson - Hal and Lois' fourth son. He is the youngest brother of Malcolm, Reese, and Francis, and often falls victim to their pranks. Dewey is very intelligent and musically gifted. Despite his intelligence, he is placed in a remedial class for slower students (or Buseys) due to a misunderstanding. Dewey remains in the class and serves as their self-appointed teacher. By the seventh and final season of the show, the Busey class is no longer mentioned. He is the youngest member of the family until Lois gives birth to Jamie. Dewey is played by Erik Per Sullivan.
- Francis Wilkerson - Hal and Lois' first son. At the beginning of the series, he is attending military school in Alabama, run by the strict Commandant Spangler (Daniel von Bargen). He has himself legally emancipated at the start of Season 3, leaves the school, and travels to Alaska. He finds work at a logging camp and later meets and marries Piama (Emy Coligado), a woman of Inuit heritage. When the camp closes, they move to the western United States and take jobs at a Wild West-themed hotel/ranch, run by kindly but eccentric German, Otto Mannkusser and his wife, Gretchen. Francis and his mother are in a mutual love-hate relationship. Although a juvenile delinquent, he is street-smart. Francis is played by Christopher Masterson.
- Hal Wilkerson - Hal is married to Lois, and is father to Francis, Reese, Malcolm, Dewey, and Jamie. Hal is an inept but caring father, and completely dependent on Lois. Hal is played by Bryan Cranston.
- Lois Wilkerson - The hot-headed and stubborn mother of the family. She struggles throughout the series to keep her badly behaved boys in check while maintaining a job at a Lucky Aide drugstore. Lois is played by Jane Kaczmarek.
- Jamie Wilkerson - Hal and Lois' fifth son, born at the end of Season 4. Despite his infancy, he is already shown to have some of his brothers' habits such as stealing and disrespecting Lois. He doesn't speak much throughout the series. Jamie is played by James and Lukas Rodriguez.
- Ida Kenzel - The biological mother of Lois and maternal grandmother of the boys.
- Victor Welker - The adoptive father/Stepfather of Lois and deceased, maternal adoptive grandfather/Step Grandfather of the boys.
- Radu Gogorsky - The biological father of Lois and the biological Grandfather of the boys.
- Susan Welker - The biological sister of Lois. It's unknown wether Victor or Radu is her true father.
- Walter Wilkerson - The neglectful and deceased father of Hal and paretnal grandfather of the boys.
- Sharon Wilkerson - The mother of Hal and paternal grandmother of the boys. Is never seen in the show.
- Claire Wilkerson - The sister of Hal and daughter of Walter and Sharon.
- Piama Wilkerson - The wife of Francis, starting with the episode Hal's Birthday.
- Raduca Wilkerson - The short-lived wife of Reese, from the episode Bride of Ida to College Recruiters.
There is some controversy about the true family name for The Wilkerson Family. Although the last name "Wilkerson" is generally stated to be their last name, their last name was never mentioned even once throughout the course of the entire series, with a few exceptions from the Pilot episode. The creators thought it would be a good idea to keep their last name a secret that would never be revealed in the series after the production for the pilot episode had been finished. In the scenes showing Francis at Marlin Academy, Francis was seen with a nametag that read "Francis Wilkerson" and this was seen in the televised airing.
In the last episode of Malcolm in the Middle, "Graduation", they decided to finally reveal what their last name was, but when they did, they did not reveal it to be Wilkerson, they revealed it to be "Nolastname". Francis was seen dropping a nametag on the ground. The nametag, when looked at very closely, read "Francis Nolastname" instead of "Wilkerson". Later, an announcer was seen saying Malcolm's first and last name, but some microphone feedback obscured his last name, making it go unheard.
There was a deleted scene from the pilot episode that was never made but seen in the script. It featured a joke where a unnamed kid exchanges dialogue with Malcolm, and Malcolm verbally reveals his last name. The unnamed kid starts talking to Malcolm about how he overheard his parents, gossiping and saying mean things about The Wilkerson parents, and then stops and says "Wait, what's your last name?" to which Malcolm responds with "Wilkerson, why?" Then the kid says "Oh, who are the Pariahs?" This episode never made it into production.
Multiple FOX promotions for the show, have used the last name "Wilkerson" to address the family.
In the episode "Stock Car Races", Francis had a fake ID with the last name "Mortenson" which he used for unknown purposes. This was obviously not his real last name because he was using this to create a false identity for himself.
In the episode "Victor's Other Family", it was mentioned that Lois' last name at birth used to be "Welker" before she got married to Hal, meaning that the family's current last name comes from Hal's side of the family. Of course, it was never mentioned what this last new name was.
In the episode "Reese Joins the Army: Part 1", Reese makes a fake identity for himself and goes under a fake age and last name, in order to make it into the army, despite him being too young. He goes by the name "Reese Jetson", but his real last name is never mentioned.
In an interview with Malcolm's actor, Frankie Muniz, he stated that Wilkerson was not their last name and that they were trying to keep their last name hidden because if they identified the characters too much, they'd limit the amount of stories that they could do with them. He also said that if they ever do another series or spin-off, they'll reveal their true last name. Conversation here.
It's unknown which one of these names is intended to be considered as canon. "Wilkerson" and "Nolastname" were both seen in the series. They tried to avoid using the name "Wilkerson", so they might have not been wanting that to be considered canon. However, "Nolastname" was an in-joke they used among the cast during the making of the show, so using it in the last episode may have been a gag. It's unknown which one is meant to be taken seriously. Overall, it could easily go either way and we could apply either last name to the family.
The Wilkerson Family has a rocky history when it comes to pets. Lois forbids the family from having pets, because she doesn't believe the family can handle one, but this rule has been broken many times, mostly by Dewey. As a matter of fact, it's a recurring theme in the show that Dewey wants a pet dog, but his parent's won't let him.
In the episode Health Scare, Dewey was seen taking care of the school's pet hamster that and kept it in his room for a while. He tried to convince his parents that by taking care of it, he can also be trusted with the responsibility of having a dog, but his parents were too preoccupied with a health scare at the time. Lance, a bully at Dewey's school reminded him that he was going to take care of it next week, and concerned for his well being, Dewey put it in a hamster ball full of food and sadly let it go away.
In the episode Reese's Job, Dewey's parents made a bargain with Dewey, saying that if he could take care of a goldfish for an entire month without having it die, they would let him get a pet dog. Dewey held up his end of the bargain, but because his parents didn't believe he'd actually be able to do it, they sabotaged him and tried to make him lose. They ultimately failed, but they still never let him get a dog in the end.
In the episode Dewey's Dog, Dewey justified the broken promise by his parents, as mentioned before as he found a stray dog and kept it for his own. Knowingly breaking his parents' rules, he snuck it into the house without them knowing. Malcolm, Reese, and Craig were the only ones who knew about it, until the dog went crazy and chased Craig away, later attacking him and never being seen again. In the episode Monkey, Craig explained to Lois what had happened and although Lois knew about it, it's not likely that she punished Dewey for it because she and Hal did promise to get Dewey a dog and they broke their rules, so they could not rightfully do that.
In the episode Ida Loses a Leg, Hal bought Dewey a pet dog, finally fulfilling the promise he made a long time ago. The dog, however, started attacking Ida's dismembered leg and started chewing it under the house. They decided to get rid of the dog for being that disgusting.
In the episode Burning Man, Hal mentioned at the end of the episode that the family had a pet cemetery. It would seem unlikely that the family would have one since they were never allowed to have any pets before.
- Ever since Hal and Lois moved into their suburban house, all of their children were born on the house's property. Malcolm and Dewey were born on the front and back yard (Flashback) and Jamie was born inside the house (Baby Part 2), leaving Francis and Reese as the only kids who were born in an actual hospital.
- Lois and Hal have brown and green eyes, respectively. However, Dewey, Jamie, and Reese are the only kids who have the same eye colors as them, (Dewey and Jamie having brown and Reese having green). Malcolm and Francis both have blue eyes, because they're portrayed by Frankie Muniz and Christopher Masterson, respectively, actors with blue eyes.
- Also, Dewey and Francis have blond hair, despite the fact that both Hal and Lois have brown hair.
- In the episode "Hal's Christmas Gift", Francis revealed that there was a popularity list for the five Wilkerson boys. From most to least popular, these were himself, Dewey, Reese, Jamie, and Malcolm.