"How Green Was My Valley" famously beat Orson Welles 'Citizen Kane' to an Oscar.
"Lux Radio Theater" broadcast a 60 minute radio adaptation of the movie on
March 31, 1947 with Donald Crisp again reprising his film role.
"Lux Radio Theater" broadcast a 60 minute radio adaptation of the movie on
September 21, 1942 with Walter Pidgeon, Donald Crisp, Maureen O'Hara, Roddy McDowall and Sara Allgood reprising their film roles.
"Lux Radio Theater" broadcast a 60 minute radio adaptation of the movie on
September 28, 1954 with Donald Crisp again reprising his film role.
"The Screen Guild Theater" broadcast a 30 minute radio adaptation of the movie on March 22, 1942 with Sara Allgood, Donald Crisp, 'Roddy
McDowall', Maureen O'Hara and Walter Pidgeon reprising their film roles performing with Rhys Williams.
Darryl F. Zanuck paid $300,000 for the rights to the novel.
William Wyler was all set to direct on location in Wales, and Laurence Olivier, Katharine Hepburn and Tyrone Power were all being courted for parts in the film.
As well as this film, the book has twice been adapted by the BBC as a serial for television, in 1960 and 1975. The 1975 production - scripted by Elaine Morgan - starred Stanley Baker, Siân Phillips, and Nerys Hughes. It was also adapted as a Broadway musical, called A Time for Singing, which opened at the Broadway Theatre, New York, on May 21, 1966. The music was by John Morris; book and lyrics were by Gerald Freedman and John Morris. The production was directed by Mr. Freedman, and it starred Ivor Emmanuel, Tessie O'Shea, Shani Wallis, and Laurence Naismith.
Cyfartha's final line, "'Tis a coward I am, but I will hold your coat," was added by Ford himself over the objections of screenwriter Philip Dunne.
For the scene where the miners greet their women by putting their earnings in baskets, actress Maureen O'Hara stopped the scene's filming once she noticed that her basket was a modern Kraft basket and not a basket of the movie's period. Director John Ford was so upset by being corrected in front of the cast and crew that he closed down the set and told O'Hara to wait on a nearby hill until he called for her. Fuming, O'Hara waited an hour before an assistant came to retrieve her but was satisfied to see that the basket had been changed upon her return.
It only took two months to make the film.
Plans to film in Wales were abandoned due to WWII; an 80-acre set was built in the Santa Monica Mountains at Brent's Crags, near Malibu. The design of the village was based on the real Cerrig Ceinnen and nearby Clyddach-cum Tawe in Wales.
The author continued the story about Huw Morgan's life in 3 sequels. 'Up into the Singing Mountain' (1960) in which Huw emigrates to Argentina; 'Down Where the Moon is Small' (1966), Huw's life in Welsh-speaking parts of Argentina; and 'Green, Green My Valley Now' (1975), in which Huw returns to Wales. None of these have been made into films, and 'How Green Was My Valley' is still the most consistently popular novel of the series.
The author of the novel, Richard Llewellyn had claimed to have based the book on his own knowledge of the Gilfach Goch area, but this was proven false, as Llewellyn was English-born and spent little time in Wales. As it turned out, he had actually gathered his facts from conversations with local mining families.
The film was shot in black and white because the color of flowers in Southern California did not match those found in Wales.