Michael Kelso, usually called just Kelso, is the intrinsiquely comical member of the Forman basement bunch, a Wisconsin 1970s version of Joey Tribbiani in "Friends": sadly low IQ, yet as good as irresistible to girls -alas except his sassy opposites- thanks to his treasured (truly) good looks and 'girlish' fashion-sence. His home isn't one, he has five or six brothers, his parents neglect him shamelessly and his older brother Casey is almost an abusive brute--another reason to hang out at Eric's.
Michael is naive and direct, childish and childlike (e.g. often doing something childlikely stupid, pranks, cheering up by simple things like ice scream of pudding, and addicted to kids TV), and he can be quit selfish, but never mean and has a heart of gold. He is all in all quite sweet and extremely entertaining. He loves all pranks, including pressing his hunky hams on just about anything, but most often gets the wrong end of the stick, especially when sadistically wielded by born bastard Steven Hyde. Fez, the other 'social outcast' with sub-standard grasp of social values, is his most compatible playmate and half in love with him. Alas Michael's horny hormones hush him to vane and vile Jackie, the one girl even he can't be happy with.
He meets Brooke at a Molly Hatchet concert, and they have sex in a bathroom stall.
He is horrified when Brooke tells him she's pregnant, and Brooke doesn't want him to be a father because Michael himself has so much growing up to do. This causes Michael to make serious efforts in maturing - he even joins the police academy and somehow makes it through and becomes a cop. Even though he greatly remains childish and childlike, he manages to convince Brooke, that he might make a good father. Michael hoped for a son, but after their daughter, Betsy is born, he loves her and even finds respect for women, who thus no longer are mainly sex objects to him. After Brooke first trusts him to take care of Betsy, Michael fears the baby doesn't like him because she wouldn't stop crying. But in the end, it seems like she does like her daddy, and Michael tells Brooke that he'd like to be more part of their child's life, that he wants to get to know her. Brooke and her own mother and baby Betsy move to Chicago, but Michael gets to be a weekend Dad. At the end of the show, Michael moves to Chicago too, to be closer to his daughter.