The Roaring Twenties (1939) is quintessential Cagney.

Mark Hellinger's story of the Prohibition era is superbly directed by Raoul Walsh, a striking look at the period between the two World Wars.

Cagney is Eddie Bartlett, returning vet who can't find work so turns to the bootlegging racket.  His former army mates are George Halley (Humphrey Bogart), who literally becomes Eddie's partner in crime, and Lloyd Hart (Jeffrey Lynn), the struggling (and quite boring) lawyer. 

Eddie has two women in his life, the faithful "has-been canary" Panama Smith (Gladys George) and the nubile Jean Sherman (Priscilla Lane).  Eddie's head-over-heels in love with Jean, but she prefers boring Lloyd -- this eventually leads to Eddie Bartlett's final downfall.

Cagney has never been better in this account of "speakeasy days, of wars between bootleggers, of underworld feuds and killings, of dizzy nightspots and of sentimental tears." (Journal-American).