He began his animation career in 1925 working for Bray Productions on the Dinky Doodle series, produced under the supervision of Walter Lantz.
On departing Iwerks's studio, Culhane briefly returned to New York to direct at the reorganized Van Beuren Corporation, then supervised by Burt Gillett, before opting to apply to Disney in 1935.
While at the Disney studio, he discovered while working on Hawaiian Holiday's crab sequence an animation method that involved stewing[clarification needed] for multiple days, before drawing the entire thing in rough sketches all at once, straight ahead.
Following the completion of Gulliver, Culhane was assigned his own unit, which he attempted to instil with the artistic principles and ethos he had acquired at Disney, yielding shorts such as Popeye Meets William Tell, notable for their unusually fluid and expressive character animation relative to much of Fleischer's previous work.
A year following his departure from Fleischer, Culhane worked briefly in the units of Chuck Jones and Frank Tashlin at Leon Schlesinger Productions, before moving on to being a director for Walter Lantz.
Following a succession of aborted projects, he returned to New York in 1948 to found Shamus Culhane Productions (Culhane had gone by his birthname of James up until this point, before going by its Irish variant Shamus), one of the first companies to create animated television commercials, among them an iconic Muriel Cigars commercial featuring a Mae West caricature stylized as a cigar.