Casting
In June 2019, James Marsden, Amber Heard, Whoopi Goldberg, Greg Kinnear, Odessa Young and Henry Zaga were all in consideration for the roles of Stu Redman, Nadine Cross, Mother Abagail, Glen Bateman, Frannie Goldsmith and Nick Andros, respectively. On July 8, Marilyn Manson confirmed in an interview with Revolver that he had been cast in an undisclosed role and also recorded a cover of The Doors' "The End" with Shooter Jennings for inclusion in the miniseries. However, it could not be used due to the series' tight budget.
By August 1, Marsden, Heard, Young, and Zaga were all cast in the series. According to news reports, Stephen King wrote an entirely different ending to the final chapter of the series that is different from either the book or coda. The last episodes were written by King and his son Owen. On September 11, 2019, Alexander Skarsgård was cast as Randall Flagg. Confirmed cast members included Goldberg, Jovan Adepo, Owen Teague, Brad William Henke, and Daniel Sunjata for the roles of Mother Abagail, Larry Underwood, Harold Lauder, Tom Cullen, and Cobb respectively.
By September 13, 2019, production on the series had begun. In October, Nat Wolff, Eion Bailey, Katherine McNamara, Hamish Linklater and Heather Graham were added to the cast. Natalie Martinez was confirmed to have a role in the series in December 2019, and confirmed that she was playing Dayna Jurgens in the comments section of an Instagram post. In January 2020, Clifton Collins Jr. revealed on Instagram that he would play the minor role of Bobby Terry. In their interview with GQ in March 2020, Ezra Miller confirmed they had a role in the series which was undisclosed but later revealed to be Trashcan Man. With this news, it was revealed that Marilyn Manson was in talks to play The Kid but that his part was cut out of the script during the writing process. In May 2020, Vanity Fair revealed the first look at Gordon Cormier as Joe.
On August 19, 2020, Mick Garris, the director of the 1994 miniseries adaptation, confirmed that he would have a non-speaking cameo in the new series. On December 3, 2020, showrunner Ben Cavell revealed during the Television Critics Association virtual panel presentation for the series that Stephen King would have a cameo.
On August 7, 2019, the Daily Moth reported that Josh Boone cast a hearing actor (Henry Zaga) over a deaf actor for the role of a deaf character, Nick Andros. This sparked a backlash from multiple well-known deaf actors. A deaf man from Los Angeles, Jared Perez-DeBusk, had a brief conversation on Instagram with Boone, sharing the exchange in a vlog and showed screenshots in the comments section. In the comments, Boone explained that the deaf character, in his dreams and when he turns into a ghost, can speak and hear, so it is acceptable to have a hearing actor because the character is both deaf and hearing depending on whether he is asleep or awake. Boone said Zaga is a dedicated actor and has been hard at work learning ASL, and that there would be deaf consultants on set. CAD Media said on Twitter that there would be a meeting on August 7, 2019, between the miniseries' production team and CBS on this issue.
In August 2020, Fiona Dourif and Irene Bedard were cast as gender-swapped versions of The Rat Man and Ralph Brentner, respectively. On December 11, 2020, Gabrielle Rose's role as The Judge was confirmed. On December 16, 2020, J. K. Simmons was confirmed to play a supporting character, later revealed to be General Starkey. Bryan Cranston has a voice cameo role as the President of the United States.
