Kermit's most well-known catchphrase is "Hi-ho, Kermit the Frog here!" He typically introduced acts on The Muppet Show by waving his arms wildly and shouting "Yay!" (a technique he learned from his old acting coach, Mr. Dawson).
Kermit grew up with thousands of siblings in a swamp. In The Muppets at Walt Disney World, it was revealed that the swamp he grew up in is located near Walt Disney World. He also has a nephew named Robin. In The Muppet Movie, he was inspired to head to Hollywood, encountering the rest of the Muppets along the way. Together, they were given a standard "rich and famous" contract by Lew Lord of Wide World Studios and began their careers. In other materials, Kermit is presented as having a friendship and partnership with his original puppeteer Jim Henson and credits Henson as being the individual to whom he owes his fame.
Kermit's relationship with Miss Piggy is prominent among the Muppets, although Kermit insists that they have a "professional relationship". In The Muppet Show, he was often pursued by her, who made no secret of her love for him, but he generally rebuffed her advances. However, he actually has gotten jealous of male guest stars that she liked and also performed a few duets and danced with her.
The "early" version of Kermit first debuted in 1955 on Jim Henson's Sam and Friends puppet show. In this iteration, he was a lizard-like, abstract creature. He had no collar or tongue and his feet were round. In later years, his identity as a frog was asserted in 1968 followed by a redesign that made his appearance closer to one.
When The Muppet Show was in development, Kermit was not intended to be the main character. It was suggested to Jim Henson that he be the star instead when the pilot's original host did not work as a main character.
Kermit became a star when he hosted The Muppet Show, acting as the host and the person ultimately in charge of what went on during the show. During the first season, it seemed as if he treated his fellow cast and crew members more like employees, but later on, as the characters developed, it became clear that they were his friends as well.
The Muppet Movie revolved around Kermit's journey to Hollywood and the new friends he encountered along the way, friends who shared his dream to make it big in show business. In the film, he meets a Hollywood agent named Bernie while playing his banjo and singing "The Rainbow Connection". Bernie discovers his talent and inspires him to set out for Hollywood. For a chance to make "make millions of people happy", he heads west for auditions. He comes to the El Sleezo Cafe where he meets Fozzie Bear, who performs in front of a booing audience and Kermit helps him by dancing. He later invites Fozzie to join him in Hollywood. However, a businessman named Doc Hopper wants him to star in his French Fried Frog Legs restaurant chain, he denied the Doc's requests. Coming near an old church, they encounter Dr. Teeth and the Electric Mayhem and their manager, Scooter, who help them avoid being spotted by Doc Hopper. After being joined by Gonzo and his chicken girlfriend, Camilla, they stop at a county fair where they meet Miss Piggy, who instantly lays eyes on Kermit upon winning a beauty pageant.
Later, they go out on a date and Miss Piggy received a phone call and leaves, leaving Kermit depressed. Kermit receives a call from Doc Hopper who says that he captured Miss Piggy and orders him to come outside, which he does and gets captured as well. Fortunately, Miss Piggy attacks Doc's henchmen and frees Kermit. After she receives a call, she leaves. Rowlf joins the group afterwards and Miss Piggy rejoins. Soon, their car breaks down and they became stranded. Kermit feels upset, thinking that he let everyone down. His conscience tells him that whether he promised something or not, they wanted to come, not because they believed in him but in their dreams. Then, Dr. Teeth, the Electric Mayhem, and Scooter reappear and give them a ride on their bus.
On their way, they are stopped by Doc Hopper's sidekick, Max, who warns Kermit about Snake Walker, a frog-killer that Doc hired, who is going to kill him. He decides to do a showdown with Doc in a ghost town where they meet Dr. Bunsen Honeydew and his assistant, Beaker. Kermit tries to talk Doc into backing off so he and his friends can follow their dream, but Doc orders his men to kill them until they are scared off by Animal who had grown from eating Honeydew's Insta-Grow Pills.
The gang finally arrives in Hollywood and asks Lew Lord to audition, which leads him to prepare the "standard rich and famous contract for Kermit and Company". They make their first movie, which is about what they've done before that the audience watched all along. An accident occurred, causing the sets to collapse and explosions to occur. After the smoke clears, a rainbow stream appears through the now-damaged ceiling of the soundstage and all the Muppets attempt to make their first movie about their experiences. However, the first take suddenly erupts into a catastrophic accident that forms a large hole in the roof through which a portion of rainbow shines through on them. They all (including the Sesame Street cast) sing one last reprise of "The Rainbow Connection" as the film ends.
Kermit, Fozzie, and Gonzo play newspaper reporters for the Daily Chronicle. Kermit and Fozzie, specifically, are playing identical twin reporters, which becomes the source of a running gag - supposedly, nobody can tell they are twins unless Fozzie wears his hat. They are eventually assigned to investigate the theft of valuable jewels from fashion designer Lady Holiday. They travel to London to interview her and stay at the dilapidated (but free) Happiness Hotel. When Kermit seeks out Lady Holiday in her office, however, he instead finds Miss Piggy, the love of his life, and fails to recognize her, mistaking her for the fashion designer.
At a nightclub restaurant, Kermit and Miss Piggy dance together, unbeknownst that Lady Holiday's necklace is stolen by her jealous brother, Nicky, and his assistants, the true jewel thieves. During the robbery, Miss Piggy's charade is revealed and she leaves Kermit behind. The next day, in a park, Kermit tells her that she lied to him because she fell in love with him and warns her that Nicky (who she was dancing with) was a jewel thief, but she retorts to him that he is jealous and they get into an argument, upsetting her. They apologize to each other and take a bike ride around the park.
After taking part in a swimming opera concert, Miss Piggy is framed for the necklace theft by Nicky's group, leaving the group the opportunity to steal an even more valuable prize: The Fabulous Baseball Diamond. However, Gonzo overhears them and warns Kermit's crew, giving them no choice but to intercept and catch the thieves themselves in order to vindicate Miss Piggy. Kermit, disguised as a prison lawyer, visits her prison and explains to her that he and the other Muppets will get her out of there and stop the thieves from stealing the diamond to prove she is innocent, and they share a spontaneous kiss.
The Muppets get to the Mallory Gallery and get to the Baseball Diamond at the same time as the thieves use it in a game of keep-away and later baseball. Miss Piggy, meanwhile, has escaped from prison and finds a motorcycle which she uses to crash into the gallery's window, knocking Nicky, who is holding Kermit hostage, out in the process. As the police arrive, she is cleared from all charges, the thieves are arrested, and the Muppets get their deserved credit for foiling the heist. They then return to America the same way they departed, being thrown out of the cargo hold and parachuting back to Earth.
In The Muppets Take Manhattan, Kermit writes a musical called Manhattan Melodies, which he attempted to put on Broadway. He also works part-time at Pete's Luncheonette and wears a few disguises in his attempts to sell the show to Broadway producers. While having amnesia after getting hit by a cab, he takes a job as an Ocean Breeze producer with three other frogs, Bill, Jill, and Gill, until his real friends find him and whisk him away to the theater. Miss Piggy restores his memory with a punch after he mocks the idea of romance between a pig and a frog. During their big Broadway premiere musical finale, she tricks him into marrying her. This later played a major role in the 2011 film.
In 2002, Kermit was featured in the direct-to-video release Kermit's Swamp Years, which offered a glimpse into his life in the swamp as a young frog. Kermit was one of the main characters in the full-length TV movie It's a Very Merry Muppet Christmas Movie. Loosely based on the classic film It's a Wonderful Life, he learns what the world would be like if he was never born.
Kermit was the main character once again in the 2011 film The Muppets, alongside new Muppet member Walter. Disney's official description of his role in the film is as follows:
“In Disney's The Muppets, Kermit the Frog lives a quiet, solitary life. It's been a few years since the Muppets last performed together and Kermit doesn't realize how much he misses his friends until he's tracked down by Walter, Gary and Mary from Smalltown, USA, and convinced to reunite with the rest of the Muppets to save Muppet Studios.
Returning to the role he made famous in six previous Muppet movies, The Muppet Show and countless TV specials and internet videos, is Kermit. "I've played other parts, like Bob Cratchit in The Muppet Christmas Carol and Captain Smollett in Muppet Treasure Island, says Kermit, "but I think me is my favorite part."
The role is a bit of a departure for the frog known for his unifying spirit and award-winning songs like "The Rainbow Connection." "The movie is filled with comedy, music, and adventure—like all the Muppet movies," says Kermit. "But I play quite a dramatic role. You see a side of me that maybe you haven't see before—and I'm not just talking about new camera angles. Acting wise, I really stretch to play me. One of my favorite moments is singing a brand new original song called 'Pictures in My Head.' I walk through the halls of a big mansion looking at portraits of my Muppet friends and missing those guys. It was very emotional… and I think it will disprove critics who've said 'the frog can't emote.'" He, who's always the glue that holds the Muppets together, has a big job in this movie, going head to head with Tex Richman—a guy who's lost his laugh—to save the studio.”
A statue of him and Jim Henson was erected on the campus of the former's alma mater, the University of Maryland, College Park.
He is the only amphibian to have had the honor of addressing the Oxford Union.
In Sesame Street: A Celebration - 40 Years of Life on the Street, his catchphrase is spelled "Heigh ho" like the rather than "Hi ho". It is also a musical chant performed by the dwarfs in Snow White and the Seven Dwarfs.
He makes a cameo in Disney/Touchstone's 2011 CG film Gnomeo & Juliet on the front of Mr. Capulet's T-shirt.
Jim Henson's last appearances as Kermit on Sesame Street includes a Sesame Street News Flash segment in which he interviews a bird whose parents live in different trees and the song "I Wonder 'Bout the World Above Up There".
When Steve Whitmire was mailed the Kermit puppet for the first time, he noticed that it "smelled like Jim." When he put it on to perform in front of a mirror, he had it turn around to him, seeming to be encouraging him to say something. He was so scared that he shelved it in another room and didn't even look at it for almost a month.
He, unlike most Muppets (and frogs), has five fingers on each hand.
In a November 2011 appearance on George Stroumboulopoulos, he says he has transparent eyelids.
However, in an interview with him and Ross Lynch for Muppets Most Wanted, he states that none of the Muppets ever blink.
He appears to have a crush on Mila Kunis: During the Muppets' appearance on Google+ Hangout, Miss Piggy demanded to know why he was looking up "Mila Kunis images."
In the 1990 TV special The Muppets at Walt Disney World, he mentions to have known Mickey Mouse for a long time and that the two of them are both members of F.A.S.A. (Fictional Animal Stars of America).
On April 18, 2015, a new species of glass frog Hyalinobatrachium dianae (Diane's bare-hearted glass frog) was discovered with an uncanny resemblance to him. Comparisons between them became viral following images posted of the glass frog's discovery.