Production notes

The script was written by Philip Dunne. He later recalled reading the original novel "in horror, turgid stuff, long speeches about Welsh coal miners on strike." William Wyler, the original director, saw the screen test of McDowall and chose him for the part. Wyler was replaced by John Ford. Fox wanted to shoot the movie in Wales in Technicolor, but it was impossible to do so during World War II. Instead, Ford had the studio build an 80-acre representation of a typical Welsh mining town at Brent's Crags (subsequently Crags Country Club) in the Santa Monica Mountains near Malibu, California. John Ford originally hired Rhys Williams, the film's Welsh dialect coach, to record the film's narration as Older Huw. Shortly before release, he had the narration re-dubbed by Irving Pichel, afraid that audiences might recognize Williams' voice from his onscreen role as Dai Bando and be confused. Williams' narration was still used in some prints of the film, including the original British release, and he's credited as such on some secondary sources.

In his October 29, 1941 review in The New York Times, Bosley Crowther praised the production as "a motion picture of great poetic charm and dignity, a picture rich in visual fabrication and in the vigor of its imagery, and one which may truly be regarded as an outstanding film of the year." On review aggregator Rotten Tomatoes, How Green Was My Valley held, as of August 2026, an approval rating of 93% based on 89 reviews, with an average rating of 8.0/10. The site's critics consensus reads: "Nostalgic without becoming maudlin, this working-class drama is enlivened by a terrific cast and John Ford's ineffable directorial eye." On Metacritic, the film holds a weighted average score of 88 out of 100 based on 17 critics, indicating "universal acclaim". Tim Dirks of Filmsite lauded the film as "one of John Ford's masterpieces of sentimental human drama." While the opinion among the Academy Awards committee that it was 1941's Best Picture has been disputed by some later critics, How Green Was My Valley continues to be well received in its own right and, in 1990, was added to the American National Film Registry. Academy Award-winning actor and director Clint Eastwood named it as one of his favorite movies. The film has been criticized in the UK for the actors' poor accents.