Pre Karate Kid
Daniel LaRusso meets Johnny and his friends who all compete for Cobra Kai in the All Valley Tournament, with Johnny being the two time defending champion. Daniel then trains with Mr. Miyagi in his own style to fight Johnny in the All Valley. Daniel eventually wins with the crane kick to the face, and becomes the new champion.
Although not held, the aftermath from the 84 Tournament is shown as Cobra Kai's sensei John Kreese destroys Johnny's 2nd place trophy and attempts to choke him, only to be stopped and defeated by Miyagi. Johnny and the rest of the students likely resign from Cobra Kai following this incident, as they finally realize how cruel and unethical of a man Kreese truly is.
Months following the aftermath of the 84 tournament, Kreese is revealed to be broke due to having no students in the last several months, but Terry Silver (true founder of Cobra Kai and friend of Kreese) decides to help him get revenge on Daniel and Miyagi. Daniel wants to fight in the next All Valley in order to defend his title, but Miyagi requests him not to. While Daniel accepts Miyagi's requests,he is soon brought in by Terry, who tricks him into thinking he wants to train him, however his true intentions are to make Daniel believe he is strong and during the tournament Mike Barnes will defeat and humiliate Daniel, which will re-popularize Cobra Kai and make everyone enroll, and he'll be able to reopen and run it with Kreese. During the finals of the All Valley Tournament Mike under Silver's order repeatedly wins a point but then commits an illegal move, resulting in him losing the point so that he has more chances to attack Daniel and cause him pain as Silver wants to to suffer more than just lose. Mike severely injures Daniel. However, in the sudden death round Daniel uses a trick he learned from Miyagi to flip Mike and win the tournament for the second year in a row, ended Cobra Kai for good (or so it seems).
Pre Cobra Kai
In the 33 years between the third film and Cobra Kai the only known champion is Xander Stone who won the tournament in 2017.
34 years after the 1984 tournament, Johnny, who has been down on his luck since the tournament, decides to re-open Cobra Kai and redeem himself. Johnny trains his students throughout the course of a few months and proceeds to have Cobra Kai unbanned from the All Valley after the events of Part III, much to the dismay of Daniel who attempts to make the ban last. Cobra Kai is unbanned and the students fight, and eventually, through the challenge of Miguel Diaz and Robby Keene, Cobra Kai wins the tournament, and have a new found popularity.