PersonalityEditApart from acting incredibly stupidly, Kelso has also been known to be quite sensitive. In one episode, when he started wearing a leather jacket, his friends started to make fun of him for looking like the Fonz from Happy Days and he kept sulking every time someone brought up this supposed similarity. This trait was also shown after an off-screen accident with mashed potatoes in the school cafeteria (he slipped in mashed potatoes and rammed his manhood into a pole), leading to the nickname "Tater Nuts," which he greatly despised.
Kelso failed first grade for his refusal to write in cursive (and also an incident where he "might have" killed the class bunny)  and lied about his age ever since. On a trip to potential colleges, he said he had been dropped on his head as a child. In the third season premiere, "Reefer Madness," Kelso was shown in a flashback as a 13-year-old, stating that he's lost all interest in school and academic aspirations, suggesting that he wasn't always as dumb as he often appears to be. However, in an even earlier flashback, it shows him as a young boy who greets the Formans with no pants, since he forgot to put them on, contradicting the earlier flashback that showed him as a smart geek when he was a child. Because he has kept his real age a secret from the rest of the gang, everyone holds a grudge against Kelso because he did not use his age to their advantage and buy them beer.
Kelso enjoys a good "burn," a painful humiliation to someone. He screams "Burn!" anytime anyone says a burn but most of the time he doesn't know what some of the words used in the burn mean. Also Kelso is known to be very unfaithful in relationships, thinking one girl isn't enough, a lot of his advice on relationships is to get two girlfriends. He has been caught cheating by Jackie two times, once hearing about it and secondly seeing it herself, watching him kiss Laurie (even though at the time he was leaving her for Jackie).
Kelso's interests include drinking beer, watching Christmas cartoons, playing with Rock 'Em Sock 'Em Robots, wrestling with dogs, playing Atari Pong, buying toy dinosaurs, and dreaming of being a spaceman. Kelso also engages in incredibly stupid activities of his own design, such as skiing off the tops of moving cars, and sliding down a rocky mountain slope in a canoe. He seems to have an affinity for falling off the town water tower, at one point claiming to have fallen in "every grade," and even does so on purpose in the series finale. He also claims that once you've already fallen off the tower, you know what's going to happen so than you can do a flip or something in that fashion. He has suffered all sorts of consequences for his idiocy, ranging from gluing his hand to the Formans' fridge to burning himself while underwater, but by dumb luck, he manages to avoid being seriously injured or killed. Kelso appears to enjoy the music of Led Zeppelin, Foghat, Pink Floyd, Molly Hatchet, Aerosmith, David Bowie, Todd Rundgren, and Peter Frampton. Kelso is also secretly a Styx fan.
Kelso accidentally shot Eric Forman's pet hamster, Snowball, with a BB gun. Later, he almost shot Steven Hyde in the shoulder, but Hyde led Kelso to believe that Kelso had actually shot him in the eye so to get Kelso back Hyde led Kelso to become so guilty that he let Hyde shoot him with a BB gun only to show Kelso he hadn't been shot in the eye and Hyde shot him in the butt. As a running gag in the series, whenever Hyde and Kelso engage in a fight, it usually ends with Hyde "supposedly injuring" one of Kelso's eyes, prompting him to shout "Ah, my eye!" or a variation of such. Kelso once wore a pair of ski goggles to avoid this, so Hyde just kicked him in the shin.
He is also known for giving not so smart advice to his friends, but it often turns against him, and then he always refuses to admit his own advice applies to him as well.
Kelso has also shown a level of commitment. Despite cheating on Jackie, he never cheated on his other girlfriends (although one of them, Laurie, ironically cheated on him). Additionally, after getting back together with Jackie, Kelso never cheated and was even angered when she kissed another man. Throughout the series, however, Kelso frequently came on to Donna and attempted to grope her. In the fourth season, he complains about being the only one of the group not to see Donna's chest so much that she is forced to flash him when upon sight of her chest he faints.
Although apparently possessing below average intelligence, Kelso is often shown to be merely unmotivated and dimwitted; he possesses a great deal of practical knowledge, which he simply fails to apply. His friends were all startled by his (comparatively) high scores on the SAT (1030) exam, and he demonstrated surprising technical insight by formulating a successful method for upgrading a Pong machine with Red in order to make the paddles smaller, thus making the game harder. The episode The Keg demonstrates that, when properly motivated (by either beer, money, or a combination thereof), Kelso is capable of solving complex algebra problems in his head.
Relationship with Jackie BurkhartEdit
When the show debuted, Kelso was dating Jackie Burkhart, a popular and self-centered cheerleader. The two lost their virginity to each other after Kelso and his friends got out of jail for riding in a car that was mistaken for being stolen. Jackie gets on Kelso's friends' nerves on a daily basis and Kelso repeatedly said that he was going to break up with her. However, Jackie beat him to it and broke up with him after hearing about him kissing Pam Macy, only to get back together in the very same episode. Jackie later broke up with Kelso again after a pregnancy scare, but they got back together later at the Junior Prom.
In Season 2, Kelso began an affair with Eric's promiscuous sister, Laurie, about which Jackie eventually found out and subsequently broke up with him again. Kelso then continued to date Laurie, until later in Season 3 when he found out Laurie had cheated on him. Soon after, Jackie decided to test Kelso to see if they should get back together, which they did. Kelso remained loyal to Jackie after that and stayed with her throughout Season 4. However, after Kelso had neglected Jackie by joining a modeling agency, Eric caught her kissing her boss, and held it over her head. Kelso eventually found out, and went to ambush Jackie's boss, not knowing he was a blackbelt. Kelso is beaten up by Jackie's boss, and he is angry at her for a while, until she tells him to find out why she cheated. She says she cheated because she was neglected. Kelso finds out he cheated because Jackie always insulted him and made him feel bad about himself, and broke up with her because he felt he couldn't be with someone who made him feel like that. The thoughtless insults Jackie constantly gave him caused Kelso to feel insecure about himself and his relationship which ultimately caused him to cheat on her in a self-conscious way of getting back at her. The reason why he didn't do the same with Laurie is because she actually did it with him whenever he wanted to, something Jackie never did. The break up didn't last, as they got back together shortly after.
In the Season 4 finale, Jackie asked Kelso to marry her, but Kelso became nervous and left for California with Donna. When he returned in the beginning of Season 5 he found out that Jackie had moved onto Hyde, which made him extremely jealous, and he spent the majority of the season trying to get her back. However, by the beginning of Season 6, Kelso had claimed to be over Jackie and was fine with just being friends with her. At the end of Season 7, Kelso drove Jackie to Chicago after her break-up with Hyde. When Hyde followed her there to propose, he found Kelso naked and in a towel, making a comment that implied he and Jackie were about to have sex. Although Kelso frequently makes sexual comments to every female on the show, including Jackie and Donna, Hyde believed the two really were about to engage in sex, and drove off to Las Vegas, effectively ending his relationship with Jackie.
In Season 8, Kelso claimed he still loved Jackie and considered marrying her before he was offered a job in Chicago. By that time, Fez had already told Jackie about his proposal, which made him feel he should do so, but she eventually turned him down, which led to just friendship between the two of them for the rest of the show.
It is clear from Jackie and Kelso's relationship that Kelso definitely is not the one wearing the pants in his relationships; he is easily manipulated (Laurie pointed this out once and called him a "tool") and never fulfills his promise of breaking up with his girlfriend, although later it may simply be because he is afraid to break a woman's heart. When he dates Annette in Season 5, he even remarked "It's good to be under someone's thumb again!" with a grin, suggesting he prefers his women to be controlling. After uttering this line, Fez asks him "What did your mother do to you?" which Kelso answers with a stupid grin.
In the Season 6 opener, it is revealed that Kelso is allergic to eggs - right after he downs a glass of raw eggs. Also, in that same season, Kelso became the illegitimate father of a baby girl, Betsy (born Bethany Victoria Kelso, named after his grandmother's first name and mother's middle name), who was conceived in a bathroom at a Molly Hatchet concert.
Kelso became a policeman, albeit a bumbling one. He attempted to take his job seriously by growing a mustache and calling himself "Mike," and even going as far as flushing Hyde's marijuana stash down the toilet, but he was quickly reverted when Hyde and Fez shaved his mustache and made him resemble Adolf Hitler. He eventually set the police academy on fire via a flare gun, and even before then, broke into the academy and lost his supervisor's squad car.
Kelso often remarks that he has an entire future planned out for him. He says this several times in the third and fourth season. This was apparently a way to convince others he was mature, but his friends viewed it as boastful and annoying. Kelso's only plan was to get through life on his good looks, and when he believes this might not happen, he greatly over-reacts. He also fell off the water tower every year since Jr. High, a fact either explaining or explained by his idiocy.
Ashton Kutcher failed to renew his contract for the eighth and final season of the series. So after the seventh season ended, Kutcher appeared in a recurring guest role in the first four episodes of Season 8.
In his first guest appearance which is the eighth season premiere episode "Bohemian Rhapsody", he is avoiding Hyde after he caught him about to have sex with Jackie in a motel room. When Hyde finally catches Kelso, he punches him in the face and resolves the issue right then and there because everything he wanted to say was in that one punch and their friendship continues on. In the following episode, Kelso is thrilled to meet Hyde's new wife Samantha because of the fact she's a stripper.
Sometime after Samantha arrives, Kelso, Fez and the gang's new friend Randy decides to throw Hyde a surprise bachelor party but Kelso forgets his part of the plan to lure him to the Formans' house where they plan to throw the party. Kelso and the others wind up in jail for a while and Kelso ends up losing his job on the police force.
In his de facto final appearance on the series, Kelso claimed he still loved Jackie and considered marrying her before he was offered a job in Chicago as a security guard for a strip club from a sleazy owner (played by Bruce Willis). By that time, Fez had already told Jackie about his proposal, which made him feel he should do so, but she eventually turned him down, which led to just friendship between the two of them for the rest of the show. In his last scene, he joins Hyde, Fez, Donna and Jackie in a Circle in the Formans' basement before departing for Chicago. He is never seen or heard from again but he is mentioned occassionally.
He makes his fifth and final appearance in the series finale episode which is That '70s Finale in which he returns to Point Place to spend New Year's Eve with his old friends.
Kelso's maternal grandmother's name is Bethany, after whom his daughter, Betsy, is named (although he did mention that Brooke named the baby). He has an older brother, Casey Kelso, and it is known he has at least four more brothers and at least one sister, who Hyde mentions in Season 2 is implied to be unattractive. In the episode, "Stolen Car," Eric Forman states that Kelso's parents have seven kids.
His grandmother, mentioned in the episode Dine and Dash, has, in Kelso's words, "big honkin' whiskers". Despite Kelso's protests his own mom is very beautiful, Jackie insists she too has the same whiskers.
Kelso's father, John Kelso, appeared in the episode Career Day, portrayed by Francis Guinan. John Kelso's office job as a specialized statistician is unclear and confusing to Michael, who decides to sum it up by saying his dad is a farmer. Kelso later wrote in his report for career day that him and his dad picked fresh carrots of the trees.
In the season 3 episode "Romantic Weekend", Red and Eric have a discussion where they both refer to Kelso's parents as being "As dumb as he is."
Kelso's wardrobe consists mainly of Izod-Lacoste (now just Lacoste) brand polos, plaid long-sleeved shirts, and bell-bottom pants.
- Kelso once thought that he heard his name on "Led Zeppelin II," believing that on "Whole Lotta Love," Robert Plant sang "Kelso Lotta Love."
- Kelso loves Popsicles, Kool-Aid, dogs, wrestling and football. He also greatly enjoys a good burn, even at his own expense.
- Over the course of the series, Kelso has had three cars: A 1965 Dodge A-100 van, a Volkswagen Samba Bus, and an MG Midget.
- Often, another character will mention Kelso doing something stupid (for example, lighting himself on fire as mentioned in the episode "The Acid Queen" or eating gum off a parking meter as mentioned in the episode "Hyde Moves In"). Kelso will reply that he did it on a dare and made $1.
- Kelso always carries a firecracker with him, and has needed it twice; once when he needed to blow down a street sign, and another, he used to bribe a boy at the library.
- Kelso is the apparent inventor of the "firecracker suit" which is mentioned several times and was first used on June the 4'th. He seems also to have an odd preoccupation with fireworks, which is mentioned in many episodes, particularly the finale.
- A running gag in the series is when Kelso starts laughing hysterically for no apparent reason in the circle. It was started when Ashton Kutcher broke character during the filming of the first circle scene after a comment made by Fez (Wilmer Valderrama).
- As seen on the show's website, (That70sshow.com) that Kelso's astrological sign is Virgo.
- Despite his long absence during the eighth and final season, he still appears on the front and back cover of the eighth season's DVD.
- Kelso is allergic to eggs
- Kelso smells like cabbage. And he liked it that way. As stated by Jackie in Season 2.
- In "Halloween" its revealed that Kelso was a year older than the rest of the gang because he had to repeat the first grade.