It all began because CBS head honcho William S. Paley was a big Philip Marlowe fan and decided that the time was right for an adult western. Paley asked that a hardboiled western featuring a Philip Marlowe-type character be developed. A script -- "Mark [sic] Dillon Goes to Gouge Eye" -- soon materialized, based on a script for the Michael Shayne radio series. Two audition scripts were used and one, featuring actor Howard Culver, was given the go-ahead. A contract problem arose with Culver and the script was shelved for three years when Norman Macdonnell and John Meston discovered it while creating a series of their own. Macdonnell, a producer, and Meston, a writer, were looking for an alternative to such juvenile western fare such as The Lone Ranger and The Cisco Kid*. Gunsmoke premiered on April 26, 1962 in the episode "Billy the Kid," scripted by Walter Newman.
Cast as Matt (not Mark) Dillon was veteran actor William Conrad, who did much to develop Matt Dillon's character. In the first episode, Chester was an unnamed "Townsman." Conrad saw the possibilities of the character and Chester was born. Baer gave Chester the last name of Proudfoot during an early rehearsal. (Chester's last name in the television show was Goode.) Chester soon developed into Matt Dillon's "assistant," and later to "deputy." Charles "Doc" Adams began as a somewhat dark character and had several conflicting backstories, the most interesting of which had the character originally named Calvin Moore, a Boston educated doctor who fell in love with woman in Richmond, Virginia. A rival for the woman's hand forced Moore into a duel in which the rival was killed. Although it was a fair duel, Moore was a Yankee who had killed a southerner in the South and Moore was forced to flee. The girl followed him and they were married in St. Louis. Two months later, Moore's wife died of typhus. Moore spend seventeen years wandering about, finally settling in dodge City and taking the name "Charles Adams." The Charles Adams name, by the way, was suggested by Conrad as a nod to the famous New Yorker cartoonist Chas. Addams. (Doc's first name was changed to Galen for the television show.) Georgia Ellis was not Miss Kitty in the first episode. Instead she played Francie Richards, an old girlfriend of Dillon. Miss Kitty soon appeared, though, first as a dance hall girl at the Long Branch, and later as the owner of the saloon. Implied but never stated was Kitty Russell's background as a prostitute.
Gunsmoke stayed on the radio until 1961. The television version ran from September 10, 1955 to March 31, 1975, and used many of the scripts from the radio show. Conrad was given a token audition for the television show but his stocky body spoke against him. The role was given to James Arness on the recommendation of John Wayne. (Raymond Burr had been briefly considered but he, too, was too bulky.)
No matter the format -- radio or television -- Gunsmoke remains an important part of broadcast history. This is where it started, with "Billy the Kid."
* Not that there anything wrong with those shows, IMHO.