The Dalton Brothers appeared along with Lucky Luke in the first Lucky Luke cartoon, Daisy Town from 1971. The cartoon was partially an original story, which was later turned into an album in 1983, and partially a mixture of several side stories from the albums (voices by Pierre Trabaud, Gerard Hernandez Jacques Balutin, and Pierre Tornade as Joe, Jack, William, and Averell respectively). In the following cartoons, including the latest cartoon from 2007, the four brothers have appeared on a regular basis and will presumably continue to do so. When Lucky Luke was transferred to live action movies in 1991, the Dalton Brothers were there too in both movies. Joe was played by Ron Carey, Jack by Bo Greigh, William by Dominic Barto and Averell by Fritz Sperberg. The third movie, Les Dalton from 2004, was a Dalton Brothers movie rather than a Lucky Luke movie. Here Joe was played by Eric Judor, Jack by Saïd Serrari, William by Romain Berger and Averell by Ramzy Bedia.
Several Lucky Luke games have been released over the years, the earliest record of the Dalton Brothers appearing in games so far is Lucky Luke: The Video Game from 1996. They have appeared in at least one more game, Lucky Luke: Go West for PC, Nintendo Wii and Nintendo DS from 2007, and most likely they have appeared in other games.
The shortest, oldest, angriest and least stupid of the brothers, Joe Dalton is the leader of the gang who frequently masterminds their prison breaks and various schemes. Perpetually furious and motivated chiefly by an obsessive hatred of Lucky Luke and Rantanplan, Joe frequently beats up his youngest brother Averell for his dim-wittedness. Joe is quick to draw his gun but is fortunately not much of a shooter.
When the brothers split up in "To each on their own" Joe is the only one who continues robbing banks, coaches and trains while settling in a ghost town reveling in his new found wealth. He sometimes sings a parody on Lucky Luke's signature tune in which instead of "I'm a poor lonesome cowboy and a long, long way from home" he sings, "I'm a rich lonesome outlaw and a long, long way from home".
William Dalton and Jack Dalton are the middle brothers who have somewhat colorless personalities and mostly act as a buffer between Joe and Averell, calming down the former and shutting up the latter. They often repeat the same sentence: "Calm down, Joe" and "Joe, calm down". In their first appearance, Jack was a trigger-happy arms maniac and William a master of disguise but those character traits weren't kept in the subsequent albums. When Morris created the brothers, William was usually shortest of the two, but in some stories, as well as animated series, William becomes the tallest of the two. Yet their personalities stays the same.
In "To each on their own" William goes out and becomes the boss of an illegal gambling hole while Jack becomes a corrupt politician. In both cases when Lucky Luke arrives with warrants for their arrest he finds that both brothers have used their new found status to get legal impunity.
Averell Dalton is the tallest, youngest and most stupid of the Daltons. Obsessed chiefly with food, Averell is sometimes prone to eating various non-edible items such as soap, which he finds delicious. His very limited understanding of any situation and tendency to goof make him the weakest link of the gang. Averell is actually rather good-natured and not particularly interested in criminal activities, but he has almost no will of his own and simply follows his brothers. He likes rather girlish things such as sewing and dancing. As a result of his good behavior his rewards for his capture are often very low unlike his brothers.
However, as shown in several albums, Averell is perfectly capable of taking care of himself when out on his own. He boldly calls Lucky Luke out for hand-to-hand combat in the album in which he's introduced (and inadvertently triggers a brawl in the street outside the saloon he and Luke are in). And after the brothers split up in "To each on their own" Averell befriends an Italian chef who he helps by working in the kitchen, expanding the line of dishes and later becomes involved with extortion of other surrounding restaurants and Mafia practices to expand the brand. Again as Lucky Luke arrives with a warrant for his arrest, he finds that Averell, thanks largely because of his new "family" has gotten legal impunity. Despite usually being tender-hearted, Averell sometimes is quite nasty. He also has a changing relationship with Rantanplan. In some books, he seems to like him, but in others he hates him, swears about him and kicks him. Notably, despite his enormous affinity for food, Averell is a mediocre cook at best, but hates having the quality of his food questioned as seen in Dalton City, where he asks for Joe's gun when Lucky Luke criticizes his specality, curry and eggs (though the virtually omnivorous Rantanplan still likes the dish).