A member of the Freelance Police, Sam comes off as more level headed and less violent than his partner Max, albeit not by much. He typically wears a grayish film noir-styled suit, with a hat and a blue and black striped tie. In the games, he has a tendency to take everything he sees, and apparently keeps the items in a cardboard box that he carries inside his coat.
Sam is prone to long-winded sentences filled with elaborate terminology. He rarely loses his temper and is able to react to panic-inducing situations with extreme calm. When he does get angry, however, he tends to react in an uncharacteristically savage manner. In They Stole Max's Brain!, Sam shows his more violent manner of investigating than in the previous episodes, which includes beating a gorilla for information to threatening a COPS member with his revolver. It is usually, and somewhat ironically, Max that calms him down and prevents him from acting upon his anger.
He also has a very large sweet tooth, as during many of his adventures and assignments he can be seen enjoying a multitude of frozen treats such as popsicles and ice cream sandwiches, especially in the comics. In Sam & Max Season Two he becomes self-conscious about his weight, particularly when seeing his future and past selves.
Sam carries around a huge revolver. In the comics, he is quick to use it but is a very lousy shot. In the Telltale episodes he can hit any object on the first shot but is very reluctant to use it against living things, even villains. The gun is absent in the other incarnations.
Although most of the time he acts like a human in a dog costume, Sam sometimes behaves like a dog. He has growled several times in the Telltale games, and his sobbing in Sam & Max Hit the Road sounded like whining. He seems to have an enhanced sense of smell; he was able to smell where Max parked the car in Monkeys Violating The Heavenly Temple, and located the cereal aisle in Beast from the Cereal Aisle and the concession stand in Night of the Cringing Wildebeest by their non-food scents. He has also been shown to enjoy dog treats. It has been speculated that he is some sort of Irish Wolfhound.
Sam has been addressed as Samuel twice, by Bosco in The Mole, the Mob, and the Meatball, and Max in Bright Side of the Moon. Presumably, this is his real name. He is also shown to be self-image issues, as shown in Beyond the Alley of the Dolls, when he and Max see a pair of the Samulacra's underwear and imagenes what would happen if he wore it, with Max and some of the Samulacra laughing at him anonimously, then when he's done imagening, he throws the underwear in the harbor.