Gunsmoke is an American radio and television Western drama series created by director Norman MacDonnell and writer John Meston.  The stories take place in and around Dodge City, Kansas, during the settlement of the American West.  The central character is lawman Marshal Matt Dillon, played by William Conrad on radio and James Arness on television.

The TV series ran from September 10th, 1955, to March 31st, 1975, on CBS with 635 total episodes.  The first twelve seasons aired Saturdays at 10 p.m., seasons 13 through 16 aired Mondays at 7:30 p.m.and the last four seasons aired Mondays at 8 p.m.  Its longevity has runners-up questioning its primacy as longest run.  It is the longest running, prime time series of the 20th century.  Today, it still has the highest number of scripted episodes for any, U.S. primetime, commercial live-action television series.  George Walsh, the announcer for Gunsmoke, began in 1952 on radio’s Gunsmoke and continued until television’s Gunsmoke was canceled in 1975. The first 7 seasons were jointly sponsored by L&M cigarettes and Remington shaving products.
When Gunsmoke was adapted for television in 1955, the network did not appear interested in bringing either Conrad or his radio costars to the medium (his weight was rumored to be a deciding factor) despite a campaign to convince the network.  Denver Pyle was also considered for the role, as was Raymond Burr, who was ultimately also seen as too heavyset for the part.  Charles Warren, television Gunsmoke’s first director, said “His voice was fine but he was too big. When he stood up, his chair stood with him.”  The belief John Wayne was asked to pin on the badge is disputed by Warren.  Although he agrees Wayne encouraged Arness to take the role, Warren says, “I hired Jim Arness on the strength of a picture he’s done for me… I never thought for a moment of offering it to Wayne.”
In the end, the primary roles were all recast, with Arness taking the lead role of Marshal Matt Dillon (on the recommendation of Wayne, who also introduced the pilot); Dennis Weaver playing Chester Goode; Milburn Stone being cast as Dr. G. “Doc” Adams (later Galen “Doc” Adams); and Amanda Blake taking on the role of Miss Kitty Russell.  MacDonnell became the associate producer of the TV show and later the producer.  Meston was named head writer.
Chester and Festus Haggen are perhaps Dillon’s most recognizable sidekicks, though there were others who would become acting-deputies for two and a half to seven and a half year stints: Quint Asper (Burt Reynolds) (1962–1965), Thad Greenwood (Roger Ewing) (1966–1968), and Newly O’Brian (Buck Taylor) (1967–1975), who served as both back-up deputy and doctor-in-training, having some studies in medicine via his uncle which then continued under Doc Adams.

In 1962, Burt Reynolds was added to the show’s lineup, as the “halfbreed” blacksmith Quint Asper and elipsed the span during characters Chester Goode and Festus Haggen.  Three of the actors, who played Dodge deputies, Ken Curtis, Roger Ewing and Buck Taylor, had previous guest roles.  Curtis, a big band and western singer (Tommy Dorsey Band, Shep Fields Band, Sons of the Pioneers), had 5 previous guest roles including one in 1963 as a shady ladies’ man named Kyle (“Lover Boy”, season 9, show 2).

Curtis first appeared in the 1959 episode “Jayhawkers” (season 4, episode 21), where he played Phil Jacks, a Texas cowboy with Jack Elam as his boss during a cattle drive from Texas.  The second was another 1959 episode entitled “Change of Heart” (season 4, episode 32), where he played Brisco, which also starred James Drury as Jerry Cass.  The 3rd appearance is the 1960 episode “The Ex-Urbanites” (season 5, episode 30), where he plays Jesse with Robert Wilke as Pitt.  He also had a small role as an Indian named Scout in the episode “Speak Me Fair” (season 5, episode 34) in 1960.  Curtis, was reared in Las Animas, Colorado, and for a time a son-in-law of director John Ford.  In 1963, Weaver left the series to pursue a broader acting career in TV series and films.  In 1964 Curtis was signed as a regular to play the stubbornly illiterate hillbilly Festus Haggen.

The character, heretofore a comic feature, came to town in a 1962 episode titled “Us Haggens”, to avenge the death of his twin brother Fergus, and decided to stay in Dodge when the deed was done.  Initially on the fringes of Dodge society, Festus was slowly phased-in as a reliable sidekick/ part-time deputy to Matt Dillon when Reynolds left in 1965.  In the episode “Alias Festus Haggen”, he is mistaken for a robber and killer whom he has to expose to free himself (both parts played by Curtis).  In a comic relief episode (“Mad Dog”), another case of mistaken identity forces Festus to fight three sons of a man killed by his cousin.  As a side note, there is only one episode that has all 3 Actors in it playing their respective roles.  It is the 1964 episode entitled “Prairie Wolfer” (season 9, episode 16), with Dennis Weaver as Chester, Burt Reynolds as Quint, and Ken Curtis as Festus.

When Milburn Stone left the series for health reasons for several episodes in 1971, Pat Hingle played his temporary replacement, Dr. John Chapman, whose presence was at first roundly resisted by Festus, a bickersome but close friend of Doc Adams.
The back stories of some of the main characters were largely left to the imagination of the viewer. Matt Dillon spent his early years in foster care, knew the Bible, was a wayward, brawling cowboy, and later mentored by a caring lawman.  Kitty Russell, born in New Orleans and reared by a flashy foster mother (who once visited Dodge), apparently had no living family.  Barkeep Sam was said to be married but no sightings of a wife were made (In the episode “Tafton”, he is seen side-by-side with a woman in a church singing).  Quint Asper’s white father was killed by white scavengers.  Thad Greenwood’s father, a storekeeper, was harassed to death by a trio of loathsome ne’er-do-well thieves.  Chester Goode was known to be one of many brothers raised by an aunt and uncle, and he mentions his mother on one occasion; he referred to past service in the cavalry, and years as a cattle driver in Texas.  The cause of Chester’s stiff right leg was never given, but it was shown as his own leg and not a prosthesis.  No direct reference was ever made to his disability in the script, although some oblique moments painted the free spirited, comic deputy with a darker tone.  Newly O’Brien was named after a physician uncle, who ignited his interest in medicine.
While Dillon and Miss Kitty clearly had a close personal relationship, the two never married.”  In the episode “Waste”, featuring Johnny Whitaker as a boy with a prostitute mother, her madam questions Dillon as to why the law overlooks Miss Kitty’s enterprise.  It appears that bordellos could exist “at the law’s discretion” (meaning the marshal’s).  Miss Kitty was written out in 1974.  The actress sought more free time and reportedly missed her late co-star, Glenn Strange, who played her Long Branch barkeep, Sam.  When Blake decided not to return for the show’s 20th (and final) season, the character was said to have returned to New Orleans. She was replaced by the hoarse-voiced, matronly actress Fran Ryan (known to many as the second Doris Ziffel on CBS’ “Green Acres”).
For over a decade on television, a sign hung over Doc’s office that read “Dr. G. Adams”. Milburn Stone was given free-rein to choose the character’s first name.  The actor chose the surname of an ancient Greek physician and medical researcher named Galen.  He is first referred to in this manner by Theodore Bikel in the season 10 episode, “Song for Dying”, aired February 13th, 1965.