I've answered this question before, so here's my answer from last time:

Interestingly enough, the actual historical event itself wasn't significant or have much of an impact. It could have been forgotten, left as nothing but a footnote in a history about boomtown violence in Arizona during the late 19th century.

But it wasn't. I'll come back to that.

First, let me talk about what it actually was. The gunfight at the O.K. Corral was the climax of a larger semi-feud between two "sides": one side was formed around Wyatt Earp and his brothers. The other consisted of a semi-organized group known only as "The Cowboys" who made a living through cattle rustling. They were also involved in other criminal activities, which involved robberies.

Now, the details of what led up to the O.K. Corral are plenty and it would take time to really write it up since it involves so many individuals and events that it could fill a book. And it has.

To cut to the point, on October 26th 1881, close to the O.K. Corral in Tombstone, Arizona; Wyatt Earp, Morgan Earp and Town Marshall Virgil Earp together with Earp's friend Doc Holliday, confronted Ike Clanton, Billy Clanton, Frank McLaury and Tom McLaury. Virgil Earp, who was the Town Marshall (in western movies, this is usually titled 'sheriff' which is wrong), attempted to disarm the four men as per Tombstone ordinance no. 9: Section 1. It is hereby declared unlawful to carry in the hand or upon the person or otherwise any deadly weapon within the limits of said city of Tombstone, without first obtaining a permit in writing.

It was a tense situation to begin with. All the four men they faced belong to the "Cowboys" and Ike Clanton himself had a personal feud with Wyatt Earp for months. Clanton had threatened to kill the Earp brothers and Doc Holliday before. However, this was not a planned shootout. This was simply Virgil Earp and his deputies trying to disarm four men carrying weapons unlawfully according to section 1, ordinance no 9. While it is not known exactly who shot first, the gunfight lasted a total of 30 seconds. One man was dead, two men were mortally injured and would die within moments. Ironically, the man who had contributed the most to the tension between the two sides escaped and died six years later in an unrelated incident. He did however take the Earps (and Holliday) to court over the death of his two friends and his brother, but they were exonerated, much thanks to Ike Clanton's own testimony which was filled with so many holes and inaccuracies that it simply couldn't be believed. The "trial", which was in fact a preliminary hearing, did not get any further than that.

Now, what made the gunfight at the O.K. Corral so famous?

In 1931, Wyatt Earp: Frontier Marshal was released. It is a largely fictional biography over Wyatt Earp but it cemented everything about him and painted Earp as a hero of the frontier, standing up against bandits and other bad guys in the Old West and he became a symbol of the Wild West Lawman and gunslinger (despite not being a marshal at the time of the gunfight). It is also in this book in which this particular gunfight was introduced in a dramatized form. One might say that it wasn't the gunfight that made Wyatt Earp famous, but that the gunfight was made famous by Wyatt Earp through this particular book. In a larger social and cultural context, it was released during the Great Depression in which dime novels was a popular form of entertainment and escape. In time of hard trial, people were looking for a popular heroic figure and some found it in this dramatized, fictional version of Wyatt Earp.

This book became the basis for the whole Wyatt Earp and Tombstone legend. The book was adapted into movies and TV-shows, which in turn inspired even more projects based on this historical event. Even the name for the gunfight was taken and popularized through the title of the movie Gunfight at the O.K. Corral (1957).

To sum it up, the gunfight itself had a small significance outside of Tombstone itself and was soon forgotten. It was then popularized in 1931 together with the legend of Wyatt Earp and has from then on become far and far more distorted and dramatized throughout the years, leading up to the very popular movie Tombstone (1993) where I imagine most people get their image of Wyatt Earp and the O.K. Corral from these days.