Yosemite Sam is usually depicted as a human cowboy with a fiery temper and a hatred of rabbits to match. He is also very trigger-happy and will start firing his [trademark] revolvers, rifles, flintlock guns, etc. at any moment, he isn't the brightest of villains though - in fact he can probably be considered extremely stupid at times and is easily tricked into humiliating and/or painful situations. Like any good villain, Yosemite Sam keeps coming back despite his continual failings but he doesn't seem to be any wiser for it, still falling for the same old tricks - of course this is a trait common to many cartoon villains, not just Yosemite Sam.
Sam has also been given names like Square-Deal Sam, Sea-goin' Sam/Sam the Pirate (his name in France instead of Yosemite Sam), Sam-Duke of Yosemite, Riff-Raff Sam, Sam Schultz, Sam Von Schmam the Hessian, Yosemite Sam of Outer Space, K'chutha Sa'am, and many other aliases.
Sam is mostly an evil, grumpy, explosive, bad-tempered and loud man. Sam quickly became just as hopeless as Elmer Fudd, though he is more dangerous and only a bit smarter than him. Sam fared no better against Bugs Bunny and was soon to become hopelessly tricked by the rabbit continually. Yosemite Sam, unlike Elmer Fudd, does not fall for the same trick twice. Sam even goes to the point to shoot "Santa" if he did not give him some presents, in the 2015 spinoff New Looney Tunes.
In Looney Tunes: Back in Action, Sam becomes a manager of his own casino and serves Mr. Chairman of the ACME Corporation (who is one of the main antagonists of the second film). He tries to obtain a play card and then kill D.J. and Daffy, but failed. He served as one of the four major antagonists alongside Wile E. Coyote, Elmer Fudd, and Taz.
In Looney Tunes: Rabbits Run, Sam is the secondary antagonist, though he has more screentime than Marvin.
In Looney Tunes: Blam-a-Rooney teams up with other Looney Tunes characters to beat various villains at times.
Sam's role in "Honey's Money" is similar to Daffy's role in "His Bitter Half". However, while Daffy was the hero of "His Bitter Half", Sam was the villain of "Honey's Money".
Sam's role in "The Fair-Haired Hare" is similar to Butch Dog's role in "Wags to Riches/Millionaire Droopy". Both showing off one of their most villainous deeds to selfishly keep what they want to themselves and take advantage to kill the protagonist (Yosemite Sam to Bugs Bunny; and Butch to Droopy) upon the revelation that the desired prize will revert to the one that survives, but fail miserably.