Bogie was a medium-sized man, not particularly impressive off-screen, but something happened when he was playing the right part. Those lights and shadows composed themselves into another, nobler personality: heroic, as in “High Sierra.” I swear the camera has a way of looking into a person and perceiving things that the naked eye doesn’t register. -John Huston (who wrote the script), when asked about Bogart’s unique appeal on this movie
Roy “Mad Dog” Earle (Humphrey Bogart) was broken out of prison by an old associate who wants him to help w/ a robbery of a casino on the California-Nevada border. The two young punks who’ll be assisting are Babe (Alan Curtis) and Red (Arthur Kennedy, before he became a well-known character actor). When the robbery goes wrong (a cop is dead), Roy is forced to go on the run. Also in the mix are a loyal dog, Pard (played by Bogart’s own dog) and two potential love interests- former dancehall girl, Marie (Ida Lupino), and Okie farmgirl, Velma (Joan Leslie). Police and press are hot on his trail; he hides in the Sierra Nevada mountains.
Roy Earle: Of all the 14 karat saps… starting out on a caper with a woman and a dog.
Bogart also sent many telegrams to Hal B. Wallis and studio head Jack L. Warner asking to be cast as Earle (who was modeled on John Dillinger). Paul Muni left Warner Bros. after a contract dispute and George Raft turned down the role, so Warner called Bogart. This was the last movie Bogart made where he didn’t receive top billing; the studio decided that Lupino should have top billing, as she’d been a big hit in They Drive by Night (1940). Though Marie admires and falls for Roy, Lupino didn’t like the way Bogart treated her and his use of sarcasm. Director Raoul Walsh saw Bogart more as a supporting player, not a leading man. He wrote in his biography that Bogart complained about everything: food chosen for lunch, settings, conditions of shooting, etc.
Roy Earle: I wouldn’t give you two cents for a dame without a temper.
Roy is a lonely/romantic man; he came from a small town, as he tells Pa (the farmer he meets on the road). He falls in love w/ Pa’s granddaughter, Velma, a pretty/club-footed young woman who sees him as a friend/benefactor. Roy has emotions which run deep; he wants to give up crime and marry a “good girl.” He has a soulmate in Marie; she is weary, straight-forward, and cares deeply for him. Roy prefers the one he can’t get- of course! Bogart and Lupino have very strong chemistry here.
 Not cocky like Cagney and Muni, not psychopathic like the early Edward G. Robinson, not as smooth as Raft, Bogart is a ruthless professional with a wide stripe of sentimentality. His Roy never shirks from killing, but he doesn’t get off on it. He’s more a rebel than a gangster, a poetic soul denied respectability, a man longing for the innocence of his youth.
 Bogart’s interpretation already showed signs of the special qualities that were to become an important part of his mystique in a few more films.
Here, for the first time, was the human being outside society’s laws who had his own private sense of loyalty, integrity, and honor. Bogart’s performance turns “High Sierra” into an elegiac film.
 Many fine moments [for Lupino] with Bogey… including a memorable speech within his cabin hideout. This is one of the best portraits of a desperate outlaw in film history. A blueprint for all the antihero films that would follow over the years…
-Excerpts from IMDB reviews