Since the beginning of the 20th century, this famous story has been adapted many times for the stage, feature-length motion pictures, and animated cartoons. The earliest film version was Fox's 1921 silent version. In 1927, the novel was adapted into the musical A Connecticut Yankee by Richard Rodgers and Lorenz Hart. A 1931 film, also called A Connecticut Yankee, starred Will Rogers. The story was adapted as an hour-long radio play on the October 5, 1947, broadcast of the Ford Theatre, starring Karl Swenson. A 1949 musical film featured Bing Crosby and Rhonda Fleming, with music by Jimmy Van Heusen and Victor Young. In 1960, Tennessee Ernie Ford starred in a television adaptation. In 1970, the book was adapted into a 74-minute animated TV special directed by Zoran Janjic with Orson Bean as the voice of the title character. In 1978 an episode of Once Upon a Classic, "A Connecticut Yankee in King Arthur's Court", was an adaptation, as was the Disney film Unidentified Flying Oddball, also known as A Spaceman in King Arthur's Court. The TV series The Transformers had a second-season episode, "A Decepticon Raider in King Arthur's Court", that had a group of Autobots and Decepticons sent back to the Middle Ages. In 1988, the Soviet variation called New Adventures of a Yankee in King Arthur's Court appeared. More recently it was adapted into a 1989 television film by Paul Zindel which starred Keshia Knight Pulliam and René Auberjonois.
It has also inspired many variations and parodies, such as the 1979 Bugs Bunny special A Connecticut Rabbit in King Arthur's Court. A Knight for a Day is a 1946 Disney short film starring Goofy that is loosely inspired by the novel. In 1995, Walt Disney Studios adapted the book into the feature film A Kid in King Arthur's Court. Army of Darkness drew many inspirations from the novel. A 1992 cartoon series, King Arthur & the Knights of Justice, could also be seen as deriving inspiration from the novel. In 1998 Disney made another adaption with Whoopi Goldberg in A Knight in Camelot. The 2001 film Black Knight similarly transports a modern-day American to Medieval England while adding racial element to the time-traveler plotline.
In the Carl Sagan novel Contact, the protagonist, Eleanor Arroway, is reading A Connecticut Yankee in King Arthur's Court, specifically the scene where Hank first approaches Camelot, when she finds out about her father's death. The quotation "'Bridgeport?' Said I. 'Camelot,' Said he" is also used later in the book, and the story is used as a metaphor for contact between civilizations at very different levels of technological and ethical advancement.
"Yankee" has also greatly influenced the premier Soviet sci-fi writers, Strugatsky Brothers, and their two seminal books. In humorous Monday Begins on Saturday Merlin's character is taken entirely from the Mark Twain's book, and he often references it. Hard to Be a God is essentially a remake of "Yankee," concentrating on the moral and ethical questions of "civilizing the uncivilized." Its ending is almost identical to "Yankee": both main protagonists crumble under the weight of dead bodies of those they tried to civilize.
2011 TV series Once Upon a Time features Hank, who is originally from Earth (dubbed as the Land Without Magic) and found his way to Camelot where he gains a daughter, Violet with an unnamed women. However, he returns to his home land after the casting of the Dark Curse, which whisks him to Storybrooke.
In the Chronicles of the Imaginarium Geographica series by James A. Owen, Hank appears in several books as a time-travelling "Messenger" recruited by Mark Twain. Hank is able to travel through time and space at will using an enchanted pocketwatch, which eventually suffers a malfunction that strands him in the time stream. (Sandy and Hello-Central are not mentioned in the series.)
The television series MacGyver includes a two-part adaptation (season 7, episodes 7 & 8, 1991) in which a modern-day engineer is transported to Arthur's court, where he uses his "magic" (science) to outwit Merlin and save the king from a deadly plot.