The show was slated to be cancelled in 1967 due to low ratings, but CBS President William Paley, who was a big fan, reversed the decision. He moved the show from Saturdays to Mondays (cancelling Gilligan's Island (1964) in the process), placing it back in the Nielsen's Top Ten.

James Arness received his draft notice in 1943, and trained at Camp Wheeler, Georgia, before shipping out for North Africa. He was assigned to the 3rd Infantry Division in time for the invasion of Anzio. Ten days after the invasion, he was severely wounded in the leg and foot by machine gun fire. He lost part of his foot, and received a medical discharge from the Army. When shooting movies or television shows, any scenes that required extensive walking would be shot early in the morning, before his feet and knees started giving out. For his service, he received: a Bronze Star, Purple Heart, European-African-Middle Eastern Campaign Medal with three bronze campaign stars, the World War II Victory Medal, and the Combat Infantryman Badge.

In the radio series, Miss Kitty Russell was a madam for prostitutes. In the first couple of seasons, there were some hints at that on the television series. James Arness explained on the DVD commentary that after the first couple of seasons, they decided to drop those references to make the show more family friendly, and so Miss Kitty became just a lady saloon owner.

The gunfight between Matt Dillon and an unknown gunman that opened every episode was shot on the same main street as that used in High Noon (1952). During one filming of this gunfight, as a joke on everyone else, James Arness let the gunman win. With the anti-violence movement of the early 1970s, the opening gunfight was dropped, replaced by Matt riding his horse.

Buck Taylor (Newly) was also requested by Jack Lord for the role of Dan "Danno" Williams on Hawaii Five-O (1968) at the same time he was up for the role of Newly O'Brian.

Denver Pyle and Raymond Burr were considered for the role of Matt Dillon.

Originated in a thirty-minute format, later expanding to sixty minutes.

After sixteen seasons, the producers decided to let Milburn Stone choose Doc's first name. Stone chose Galen, which was the surname of an ancient Greek physician and medical researcher. In season 10 episode 21 SONG FOR DYING, Theodore Bikel's character "the Singer" calls Doc Adams "GALEN" and Doc calls the singer Martin Kellums.

All four senior officers of Star Trek (1966) appeared in separate episodes. William Shatner was in season twelve, episode twelve, "Quaker Girl". DeForest Kelley was in season one, episode twenty-three, "Indian Scout". James Doohan was in season eight, episode three, "Quint Asper Comes Home". Leonard Nimoy was in four: season seven, episode fourteen, "A Man a Day"; season eight, episode one, "The Search"; season eight, episode twenty, "I Call Him Wonder", and season eleven, episode twenty-nine, "The Treasure of John Walking Fox.

At twenty years and six hundred thirty-five episodes, it is the second longest-running American primetime television series to date. The Simpsons (1989) surpassed it with seasons in 2009 and with episodes in 2018.

James Arness and Milburn Stone are the only two regulars to stay with the show for its entire twenty-year, six hundred thirty-five-episode duration on CBS. There was one brief exception in 1971. Milburn Stone suffered a heart attack, and Pat Hingle, portraying Dr. John Chapman, replaced Stone for six episodes while he recovered.

In Spanish-speaking countries, the series is known as La ley del revólver ("The Law of the Revolver").

According to a TV Guide article published in the August 23, 1975 issue (just before the show left the air), twenty-six actors tested for the role of Matt Dillon. William Conrad (voice of radio's Matt Dillon) was one, but didn't look the part. Raymond Burr sounded great, but according to Producer and Director Charles Marquis Warren: "He was too big. When he stood up, his chair stood up with him" (Burr lost considerable weight to play Perry Mason). John Pickard almost made it, but did poorly in a love scene with Miss Kitty (he guest starred a few times in various roles). Warren and Producer Norman MacDonnell stoutly denied that they even considered John Wayne, but they went with James Arness, who looked and sounded a LOT like Wayne. When Arness was reluctant to take the role, Wayne persuaded him and even agreed to introduce the first episode.

This show, along with The Life and Legend of Wyatt Earp (1955), helped usher in great era of the television western. Westerns became so popular on television, that by the end of the 1950s, there would be as many as forty of them airing in primetime.

No one told the cast about the series being cancelled. Many of them read about it in the trade publications.

Dennis Weaver felt his first audition for Chester did not go well, so he begged them to let him do it again, but this time with his famous country accent. He got the part.

In the series' 20 seasons, Matt Dillon kissed only one lady: Michael Learned of The Waltons (1971) fame, in Gunsmoke: Matt's Love Story (1973).

When Dennis Weaver announced that he was leaving the show, it was Director Andrew V. McLaglen's suggestion that Ken Curtis be brought in for a tryout as Festus Haggen in a few episodes. McLaglen had directed Curtis in a similar role on an episode of Have Gun - Will Travel (1957). "Festus" was given the job of Deputy to make him different from Weaver's character of Chester Good (who was never a Deputy).

James Arness almost didn't take the part of Marshal Matt Dillon. People in the industry were telling him not to out of fear that it would hurt his chances for a movie career if the television show failed. After having a long talk with his good friend, John Wayne, he decided to accept the role.

The series was set in the 1870s. Kansas entered the Union in 1861. The Marshal's Service provided local law enforcement in territories, not in states. The duties Matt Dillon performed would have been handled by a town Marshal or County Sheriff (in this case, Ford County). Each state (or federal court district) had one U.S. Marshal, who was in charge of all of the Deputy U.S. Marshals in that particular jurisdiction; Matt Dillon would have been a Deputy U.S. Marshal.

The beginning sequence with Marshal Matt Dillon (James Arness) walking around through the graves on Boot Hill and giving the opening narration was taken directly from the radio series.

Dennis Weaver stated on his commentary about his time on this show, that he seriously regretted giving Chester his limp. He hadn't realized how much work it would become to maintain in everything Chester did.

According to "The Complete Directory to Prime Time Network and Cable TV Shows" (8th Edition, pg. 495), John Wayne was the first choice to play Marshal Matt Dillon, but he declined because he did not want to commit to a weekly Television series. He did, however, recommend his James Arness for the role, and gave the on-camera introduction in the pilot.

Gary Busey's character Harve Daley was the last man killed on the show.

In the show's twenty-year run, James Arness was the only actor who appeared in every episode.

When the show first aired in the United Kingdom, it was known as "Gun Law". This meant that the opening title sequence had to be re-filmed. Comedy writer Dick Vosburgh was picked to double for James Arness, due his similar height and build.

The actress originally offered the part of Miss Kitty, Polly Bond (Polly Ellis), turned it down due to her recent (at the time) marriage to Tommy Bond in 1953.

The series was the final film project of Glenn Strange.

"Gunsmoke" was created by Writer John Meston and Producer Norman MacDonnell as a radio series that premiered on CBS in 1952. Many of the early television episodes were adaptations of Meston's radio scripts. The radio series ran for more than four hundred episodes, and lasted until 1961.

In the radio version, Chester's last name was Proudfoot ("borrowed" from the works of J.R.R. Tolkien), but when the show moved to television, his last name was changed to Goode.

Three of the children from The Brady Bunch (1969) appeared in episodes: Christopher Knight (Peter Brady) appeared in season fourteen, episode ten, "The Miracle Man". Eve Plumb (Jan Brady) appeared in season fourteen, episode eighteen, "Gold Town", and Susan Olsen (Cindy Brady) was in two, they were season fourteen, episode eight, "Abelia", and season fifteen, episode six, "A Man Called Smith".

"Get the hell out of Dodge" is a reference to Dodge City, Kansas, which was a favorite location for westerns in the early to mid twentieth century. Most memorably, the phrase was made famous by this show, in which villains were often commanded to "get the hell out of Dodge". The phrase took on its current meaning in the 1960s and 70s when teenagers began to use it in its current form.

Rumor has it that Rex Koury had so little time to pen the theme song that he hastily scribbled it while in the bathroom. It was originally written for "Gunsmoke" when it was a radio show and later adapted for television.

Festus and Doc had a love-hate relationship. Festus would refer to Doc as "you ol' schutter you", and would often ask Doc to have a drink or share a last drink for the night, hoping the end result would be Doc paying for the drinks, because Festus would always have a reason to not have enough money to buy them both one. Festus tried doing the same relationship with the "sub" doc for the six episodes filling in, while in real-life, Doc was recovering from a heart attack, but the bond between Festus and Doc was too strong to replace, even for the short amount of time Doc (Stone) was out.

During the last ten years of the series, James Arness was suffering from severe arthritis, which got so bad, that all of his scenes for each episode were shot on a single day, allowing Arness to rest and recuperate in between.

Dennis Weaver was the first actor cast. Weaver said on the DVD commentary that he knew they were leaning towards James Arness for Marshal Matt Dillon, but he was in the Bahamas at the time filming a movie with John Wayne. They went ahead and started casting the other parts, so he ended up being the first one officially chosen for the series.

Festus (Ken Curtis) always wore his hat slightly to the right, placing it on his right ear to cause his ear to stick out slightly, sort of a "floppy ear" look.

The cast of the radio version was completely different than the television version. Playing the main roles were William Conrad as Marshal Matt Dillon, Georgia Ellis as Miss Kitty Russell, Howard McNear as Doc Adams, and Parley Baer as Chester. In fact, with the exception of Conrad, many felt that the radio cast were going to reprise their roles on the televised version.

Dennis Weaver said on the DVD commentary that the reason Chester didn't carry a gun on him was because they wanted him to be non-violent. He also said that because he was supposed the sidekick, they told him that Chester needed something to separate himself from Matt. So Weaver came up with the idea of giving Chester his famous limp.

It was originally produced for CBS by Filmcrafters at the Producers Studio (now the Raleigh Studio). Around 1960, CBS took over production and moved it to KTLA Studios, then owned by Paramount Pictures. Around 1963, production was moved to CBS Studio Center, formerly Republic Studios, where it remained for the rest of the show's run. Starting around 1970, CBS produced it in association with The Arness Company (James Arness). Originally syndicated by CBS Films and then by its successor, Viacom, now Paramount Television.

In Steven Spielberg's Duel (1971), Dennis Weaver's character stops at a filling station. As he drives off, the character who filled up his car is seen, from a distance, walking back towards the station, walking in a stiff-legged limp, like Weaver's Chester Goode character from this show.

Ken Curtis (Festus) appeared as an Indian in an original thirty minute episode.

Doc Adams first name on the show was Galen. However, on the radio version of the show, his name was Charles.

During the show's twenty season run, anytime between seasons when the writing crew was 'washed-up' with ideas/stories and kept repeating/recycling. They would entirely be replaced with a new writing crew.

Country songs have reference to Marshal Matt Dillon never putting his boots under Miss Kitty Russell's bed, or hanging his hat up at her place.

Contrary to popular belief, Chester Goode was not a Deputy. However, that job was bestowed upon Festus Hagen.

Shortly before he was cast as Festus, Ken Curtis appeared in an episode called "Lover Boy" as a love 'em or leave 'em cowboy named Kyle Kelly.

Some have rumored that the role of Chester and his limp or stiff leg was created using a rock placed in his boot to help it seem more realistic.

The name of the restaurant in Dodge City was Del Monaco's.

One reason given for why Chester's last name being Goode on the television show while his last name was Proudfoot on the radio version was because the producers of the television version didn't know if they could use it due to ownership issues. Parley Baer, who played Chester on the radio version spontaneously used the last name when the producers hadn't come up with a last name for the character.

The opening shoot out in the title sequence of TV's Gunsmoke was shot on the same street seen in the Laurel and Hardy film Way Out West.

Chester always referred to Matt as "Mr. Dillon", and Festus always referred to him as "Matthew".

Towards the end of the run, James Arness was 51, a year older than Milburn Stone was when the series started.

The back-and-forth banter and adversarial nature between Doc and Festus (the smart Doctor and the country fool), was similarly used in Star Trek between the country Doctor and the smart alien, McCoy and Spock.

For over 40 years, the show held the record for the most episodes of a scripted prime time series before The Simpsons (1989) surpassed it in 2018. (with the exclusion of soap operas etc.)

Quint Asper (Burt Reynolds) was half Commanche.

Doc's first name of Galen was probably inspired by the Greek physician and philosopher of the same name who lived from 129 A.D. to around 200 A.D.

Chester always wore suspenders.

Despite the very vast amount of guest stars, only eleven Oscar winners appeared on the show.

Amanda Blake reportedly kept 'hounding' the producers until she got cast as Miss Kitty.

Unfortunately, according to Arness, the cancellation at the end of the 20th season got them by surprise. The cast and crew were all expecting another season, three at most, at least until the series had seven hundred episodes.

Gunsmoke's 20 seasons set the record for the most seasons for a scripted prime-time drama series on American television. This record was tied by Law & Order (1990) and most recently surpassed by Law & Order: Special Victims Unit (1999).

Ken Curtis played on a previous episode as a Texas cattleman who befriended Chester, and was killed at the end of the episode.