Ralph Wolf (named after a Warner Bros. employee) has virtually the same character design as another Chuck Jones character, Wile E. Coyote: brown fur, wiry body, and huge ears, but with a red nose in place of Wile E.'s black one; (usually) white eyes instead of Wile E.'s yellow; and, occasionally, a fang protruding from his mouth. He also shares the coyote's appetite, and persistent use of ACME products, but he covets sheep instead of road runners and, when he speaks, doesn't have the upper-class accent or the egotistical bearing of Wile E. Another crucial difference is that of personality: Ralph does not have the fanatical drive of Wile E. in pursuing his prey, preferring to abandon his chase at the end of the working day.
Sam Sheepdog, by contrast, is a large, burly Berger De Brie (Briard Sheepdog) with white or tan fur and mop of red hair that usually covers his eyes. He very rarely runs and tends to be sedentary in his movements. He does, however, possess sufficient strength to incapacitate Ralph with a single punch once he catches him.
Inspired by the Friz Freleng cartoon The Sheepish Wolf of a decade earlier (October 17th, 1942), Chuck Jones created Ralph and Sam for a series of film-shorts. The first of these was Don't Give Up the Sheep, released on January 3rd, 1953.
The cartoon proved a success, prompting Chuck to repeat the formula 5 more times between 1953 and 1962. In 1963, ex-Jones animators Phil Monroe and Richard Thompson also starred the duo in their cartoon Woolen Under Where.
The series is built around the idea that both Ralph and Sam are just doing their jobs. Most of the cartoons begin at the beginning of the workday, in which they both arrive at a sheep-grazing meadow, exchange pleasant chitchat, and punch into the same time clock. Work having officially begun, Ralph repeatedly tries very hard to abduct the helpless sheep and invariably fails, either through his own ineptitude or the minimal efforts of Sam (he is frequently seen sleeping), who always brutally punishes Ralph for the attempt. In many instances there are also multiple copies of Ralph and particularly Sam.
At the end-of-the-day whistle, Ralph and Sam punch out their time cards, again chat amiably, and leave, presumably only to come back the next day and do it all again. Both Ralph and Sam were voiced by Mel Blanc. In A Sheep in the Deep, the workday is interrupted by a lunch break, which they also conduct amiably. The operation seems to run 24 hours a day or at least into another shift, as when Ralph and Sam "punch out" they may also run into their nighttime replacements, Fred and George, respectively (see Sheep Ahoy: inconsistency in naming). In some of their earlier appearances Ralph and Sam are named inconsistently: in particular the Sheepdog's shift replacement sometimes addresses him as "Ralph."
Sam and Ralph have featured in a handful of Warner Bros. projects since the closing of the studio's animation department. Sam has a cameo in the 1988 Mystery film Who Framed Roger Rabbit? during the final scene, and they occasionally feature in the Looney Tunes comic book published by DC Comics.
- Sheep, Dog, & Wolf (also known as "Sheep Raider") for the original Sony PlayStation and PC, published by Infogrames, is a faithful adaptation of the series' sheep-abducting schemes. The Road Runner makes a cameo appearance in the training level and also the final level, racing in the desert against Ralph. Ironically, neither Ralph or Sam speak within this game.
- Sam appears in the Taz-Mania episode Mutton For Nothing voiced by Jim Cummings. In this episode, Taz is sent by the Predators-R-Us temp agency to cover for Ralph Wolf while he's on vacation. Taz tries unsuccessfully to steal the sheep from Sam Sheepdog. A bit of character confusion is at play in this episode, as Sam references Ralph as being "that Coyote."
- Ralph and Sam make a brief cameo in the 2003 Comedy/Adventure film Looney Tunes: Back In Action. In the movie, Ralph and Sam are sitting at the same table eating lunch, when Ralph reveals to Sam that he finally caught a sheep, Sam grabs him by the neck and continually slaps him across the face.
- Another appearance by Sam is in Bah, Humduck! A Looney Tunes Christmas.
- Sam makes a cameo appearance in Space Jam.
- Sam appears in The Looney Tunes Show opening.
- Sam makes a minor appearance in Carrotblanca as Yosemite Sam's chauffeur.
- Ralph and Sam makes their appearance in a book called The Looney Tunes Treasury. They both have their own biography.
- Ralph and Sam also appear in the Looney Tunes DC comics.