This show, along with Gunsmoke (1955) helped launch a great era of the TV western. Westerns became so popular on TV that by the end of the 1950s, there would be as many as 40 Westerns in prime time.
Hugh O'Brian had been a member of the United States Marine Corps, and he was actually the fastest quick draw of all his fellow actors on TV Westerns. O'Brian's draw was .08 of a second.
The role of Wyatt Earp was originally offered to George Montgomery, but he turned it down because he had commitments for several western films and couldn't get out of them. Hugh O'Brian was then awarded the part.
From 1956 until 1959 the show was set in Dodge City, which was also the setting for Gunsmoke (1955). Marshall Matt Dillon is never mentioned, but many episodes take place in or around or make a passing reference to the Longbranch Saloon, a setting for much of the action on "Gunsmoke". The Long Branch Saloon was also referenced in "The Gunfight at the OK Corral" (1957) during the Dodge City sequences. The Long Branch Saloon actually existed in Dodge City, Kansas during the cowtown and cattle drive era.
Although highly fictionalized, this TV series actually followed the chronological life line of Wyatt Earp, with his moves through Kansas towns and on to Tombstone, Arizona. It is unique among westerns of the time in following a timeline throughout the entire series.