In October 2017, it was announced that 20th Century Fox was developing the film adaptation of London's classic novel, with Sanders as director and Green penning the adaptation. In July 2018, Harrison Ford set to star as John Thornton. By late September, Dan Stevens, Omar Sy, Karen Gillan, Bradley Whitford, and Terry Notary were cast. At the same time, principal photography commenced, and took place in Vancouver, British Columbia, Canada, and Santa Clarita, California. In January 2019, it was announced that John Powell will compose the film's score. MPC Montréal provided the film's visual effects. The film's producers chose to go with a CGI canine in order to give him a fuller range of emotion and expression as well as to avoid putting any real dogs at risk of being injured or frightened in this tale of overcoming hardships in a harsh environment. The fully CGI model of Buck is a digital scan of Buckley, a real dog that Sanders' wife, Jessica Steele-Sanders, adopted from an Emporia, Kansas animal shelter during production. By the time post production wrapped, the film had a $125–150 million budget.
The film stars Ford, Stevens, Sy, Gillan, Whitford, and Notary. Despite being no Clark Gable, Ford acts with pure soul here (he also narrates the film with his lovely storybook growl); it's a minimalist performance, mostly very reactive, but the saintly gruffness of Ford’s thick-gray-bearded, sad-eyed presence helps to nudge Buck to life as a character. The cast does quietly powerful work as London's beloved characters, but their computer-generated co-star looks weird.