- „If this is about maturity, I want nothing to do with it!”
- —Kelso to Jackie[src]
Tall and lanky, he is the dim-witted pretty-boy of the group, coasting through life on his good looks. His behavior is very much in line with a stereotypical oversexed lunkhead. Michael has surprised many by scoring higher on a test than some of his other friends, leading some to believe that perhaps Michael is not dumb, but just naive.
Michael failed the first grade for his "refusal" to write in cursive and accidental murder of the class bunny. He has been lying about his age ever since. On a trip to potential colleges he claimed that he had been dropped on his head as a child.
Michael is one of 7 siblings, including his older brother, Casey, at least two other brothers and a sister (whom Hyde says is an uggo; a term used by Hyde to describe someone who he does not deem attractive, which is somewhat ironic as Michael is constantly referred to as handsome, along with his brother Casey).
Michael's interests mainly include watching cartoons, having sex, smoking marijuana, playing with "Rock 'Em Sock 'Em Robots", toy dinosaurs, dreaming of becoming an astronaut, and incessantly boasting of his God-like complexion.
Apart from acting incredibly stupid, Michael is also known to be quite sensitive. Michael is shown in a flashback as a 13-year-old, stating that he is lost all interest in school and academic aspirations, suggesting that he was not always as dumb as people believe him to be. Michael enjoys a good "burn", a painful humiliation to someone. He screams "Burn!" anytime anyone says a burn.
Kelso appears to enjoy the music of Led Zeppelin, Foghat, Pink Floyd, Molly Hatchet, Aerosmith, David Bowie, Todd Rundgren, and Peter Frampton. Some of his secrets include being a fan of Styx and having a crush on Jackie Kennedy.
Kelso loves dogs. In "Eric's Naughty No-No" he cuddles in the Foremans driveway with five dogs at once. Earlier in the episode he was confessing stuff to Jackie, one of the things which was that one time they were about to fool around and he said that he had washed his hands but he had just finished playing with six dogs. In "Holy Craps!" he is excited that the Petersons have just gotten a new dog, and encourages the gang to go with him to check it out.
Michael has a long time relationship with Jackie, played by Mila Kunis, a popular and self-centered cheerleader (coincidentally Ashton Kutcher and Mila Kunis are married in real life). The two lost their virginity to each other after Michael and his friends got out of jail for riding in a car that was mistaken for being stolen. Jackie gets on Michael's friends nerves on a daily basis and Michael repeatedly said that he was going to break up with her. But Jackie beat him to it and broke up with him after a pregnancy scare. They got back together later. Michael loves a good burn as much as the next guy, even when the burn is at his expense, but generally he does not mean to severely hurt someone, which he often does but most of the time he hurts people by means of accident rather than on purpose. It is revealed on That70sShow.com that the astrological sign of both Michael and Jackie is Virgo.
Michael has an affair with Eric's sister Laurie, which leads to Michael and Jackie breaking up again in Season 2. During the next season they get back together after Jackie devises a series of tests to see if Kelso has matured. But at the end of Season 4 Jackie wants to get married and a freaked out Kelso bails on Jackie and helps Donna Pinciotti run away to California. When they return in Season 5 Michael finds out Jackie has moved on and is now romantically involved with Steven Hyde. He tries to deal with it but can not and after Hyde cheats on Jackie, he thinks he has a shot but Hyde wants Jackie back too and fights with him over her. After discovering in Season 6 that Jackie chooses Hyde who will not take her back, Michael decides to help get them back together, and wishes them the best. In the Season 6 a plotline was added that made Michael the father of a baby girl (conceived in a bathroom at a Molly Hatchet concert) with Brooke Rockwell.
In Season 7, he gets involved with Hyde's sister Angie but she breaks up with him after she is transferred to another job (which he gets angry about, although he was going to break up with her anyways). In Season 8, Kelso leaves Point Place, but before he does, he proposes to Jackie and she rejects him (which he is delighted about). It is hinted however that Jackie would have said yes if Fez had not told her first, because she had always loved Kelso and thought of him as her soulmate. He then tricks the gang in the circle into thinking that he was leaving, but was really leaving the next day.
Kelso is kicked off the force, making him happily accept a better job as a security guard for a Chicago playboy bunny club from the sleazy owner who is played by guest star Bruce Willis. He returns for New Years Eve and jumps off the water tower with Fez and Hyde (Fez and Hyde try to trick him but Michael's brilliant mind outsmarts their trick, although he then willingly jumps off the water tower anyway for the new decade). He then joins the last circle and calls Red a dumbass. He is also the last character to be seen as the show ends, grabbing the stupid helmet, as he makes his way up the basement stairs to call Red a "dumbass".
- „Is it so wrong to feel?!”
- "Damn, Jackie!"
- "Right now I'm just Jackie's friend. But what she doesn't realize is that I'm also a boy. And eventually 'friend' is gonna lead down the path to 'boy', and then I'll be her friend-boy."
- "Man, what fun is it being a girlfriend if you don't even have your own boobs to play with?"
- "If being smart isn't gonna help me with the chicks, I want nothing to do with it!"
- "When girls cheat, it's way worse because girls don't even like sex."
- "I don't get Jackie, man. I mean, picking Fez over me? Me? I have the three things that women want. I'm hot, and I'm smart!"
- "I have a question. If Hyde was in Hyde's bed and Jackie was in Hyde's bed, what exactly was going on in said bed?"
- "Eric, I'm telling you this as a friend that likes to see you get hurt.... don't give Donna that ring!"
- "It's Thanksgiving. Some people bake pies... we bake ourselves."
- "You guys want to know a funny word? Pickle-weasel!"
- "If ham's Canadian bacon, then what the hell do you call bacon?"
- "You know what your problem is? I'm too good looking."
- "It's another box of dogs!"
- "I ate gum off a parking meter once... it was on a dare. I made a dollar! Man there's some SUCKERS out there!"
- „Yeah, you know, that's a good way to hunt. Because even if you don't get anything, you still have all the fun of a whistle and a stick”
- —Kelso to Fez[src]
- "I'm not good with the snobs, but slutty is my bread and butter."
- "Alright! We're getting a fat kid!"
- „Well, damn Jackie I can't control the weather!”
- "Oh Yeah, Uh Donna I'm going to need you to pull my pants down.... Okay" "AHHH! Wedgie!"
- "Sure it is. Like, if I could only eat meat, but I had to eat really fast animals, my feet would eventually evolve into rockets."
- Throughout the series, Kelso repeatedly hits on Donna and Jackie (even when she is with someone else).
- Whenever Hyde and Kelso fight, Kelso ends up yelling "OW, MY EYE!"
- Michael can be seen wearing Nike brand shoes in several episodes even though Nike sneakers were not released to the public until the early 80's. This is a common flaw in some shows taking place in the past, as they can wear almost any shoe they want.
- In "The Kids are Alright", Kelso drinks raw eggs and goes to the hospital due to face swelling. Yet in the first season, he ate deviled eggs and even other types throughout the series and was perfectly fine. However, one can grow an allergy to any sort of substance over a period of time, even after eating it previously.
- After That '70s Show Michael's character became the basis of the personality of the characters that Ashton Kutcher would play in the future--gorgeous and goofy.
- In "Over the Hills and Far Away", it was revealed that Kelso was dropped on his head as a kid. However, he gets easily upset by this because everyone else had the grace to never mention it.
- It is hinted that Michael and Steven knew each other since they were five years old.
- It was left unknown if Michael had started dating again after That 70's Finale but it was hinted that he married Brooke; the mother of his child.
- Most of the girls in Point Place High or anywhere else find Michael irresistible.
- Kelso loves to play with dogs and fall off the water tower.
- In Season 8, Michael left Point Place for Chicago to be closer to his daughter and Brooke. The PlayBoy Club that he became the bouncer for eventually closed down in 1991.
- He once suggested calling Fez Captain Poo-face.
- He first saw Donna's breasts in Class Picture.
- Kelso is the oldest of the group, as he was born in August of 1959, surpassing Hyde by three months.
- Kelso knows how to operate a manual transmission.
- Kelso has had three vehicles over the course of the series.
- Even though he is a Packers fan, he constantly wears a purple shirt that resembles a Minnesota Vikings jersey.