Sanada is an alcoholic doctor (the titular "drunken angel") in postwar Japan who treats a small-time yakuza named Matsunaga after a gunfight with a rival syndicate.

The two enjoy an uneasy friendship until Matsunaga's fellow yakuza and sworn brother, Okada, who is also the abusive ex-boyfriend of the doctor's female assistant Miyo, is released from prison.

Matsunaga quickly succumbs to peer pressure and stops following the doctor's advice, slipping back into old drinking habits and going to nightclubs with Okada and his fellow yakuza.

On the film's Criterion Collection DVD, Japanese-film scholar Donald Richie comments that Kurosawa was impressed by the athletic agility and "cat-like" moves of Mifune, which also had bearing in his casting.

[5] The censorship board was unable to catch these subtle breaches due to overwork and understaffing, but censors did require Kurosawa to rewrite the film's original, more "gruesome" ending.

Since the end of 1947, during which the union-run studio was becoming increasingly less profitable, the union's influence on filmmaking was waning and Kurosawa managed to produce the film with minimal interference.

[3] After the film's completion, the strikes escalated, upon which Kurosawa left Toho, being both disillusioned by studio executives' attitudes to the union and by the state of siege the occupying strikers were put under by police and American military forces.

Kurosawa had the sound crew find the exact recording of The Cuckoo Waltz that he had heard after his father died, and had them play the instrumental beginning of the song repeatedly for the scene in which Matsunaga walks down the street after leaving the boss.

One loss implying a reformation of social identity whereby the progressive individual should separate themselves from the family (embodied in the yakuza), and the other being symptomatic of a "national schizophrenia" that has resulted from the Americanization of Japan.

Prince writes that the narrative and spatial confinement of much of the film close to the sump returns the action to sickness, posing the question of how recovery can emerge from a humane ethic under post-war conditions.

[11] Writing in 1959 for the New York Times, Bosley Crowther cites the film's developing "brooding and brutish mood" and "poisonous atmosphere" in his positive appraisal of its symbolic moral conflict.