The style of Up the River is in keeping with the relaxed, spontaneous mode of filmmaking that characterizes the best of Ford’s later work. Seldom revived today, Up the River is an utterly delightful, disarmingly offbeat lampoon of the prison movie genre. Fox originally commissioned a serious study of prison life from screenwriter Maurine Watkins. Ford turned it into an absurdist comedy about a midwestern penitentiary where life is so convivial that two escapees break back in for the big baseball game against a rival prison. The director did an uncredited rewrite with William Collier, Sr., the veteran actor who plays Pop, the prison’s salty but wise old lifer. Although the jocular Up the River in many ways represents the antithesis of the solemn and symbol-charged Dudley Nichols approach to filmmaking, it has thematic and structural affinities with Ford’s dramatic films written by Nichols and others about men testing their character in isolated fortresses. But it does so in a breezy, offhand, often ironic manner, brimming over with what Ford liked to call “grace notes.” By that he meant directorial touches, often nonverbal, that reveal character or capture emotion. Up the River was Spencer Tracy’s first feature film and Humphrey Bogart’s second. Tracy’s screen persona is already fully formed here as the brash, cynical, charismatic St. Louis, lionized by his fellow inmates for his pitching prowess and his indifference to prison rules. Bogart, in his early “Anyone for tennis?” phase, is excessively callow as Steve, a rich kid gone wrong. Ford’s comic imagination is most stimulated by Warren Hymer, who gives an unexpectedly touching comic performance as St. Louis’s moronic sidekick, Dannemora Dan. The occasional undercurrents of suffering and despair in Up the River only strengthen Ford’s joyous, ironic affirmation of community in this subversive film portraying prison life as preferable to the hypocrisy and emotional isolation of the outside world. 
(From Searching for John Ford)