The lead role of Dean was originally cast with Austin Nichols in March 2018, but he was recast just two months later, with Rich Sommer taking over the part in July 2018.

In the Dark is the first CW primetime series to carry Descriptive Video Service audio, even though The CW is not required to provide such audio description under regulations that apply to major networks.

The show faced criticism for casting sighted actress Perry Mattfeld as the blind protagonist Murphy, with disabled actor James Moore arguing that disabled performers are always better suited to portray disabled characters due to their lived experience.

Executive producer Nicky Weinstock defended the casting choice during a Television Critics Association panel, stating that the production initially auditioned blind actors but ultimately cast Perry Mattfeld because she was considered the best actor for the role.

Filming on the pilot took place in Toronto, Ontario, Canada, starting March 12, 2018, and wrapping on March 28, 2018.

The show was filmed across multiple Canadian locations over its run, including Toronto and Cambridge, Ontario, with each season's principal photography taking several months, from around August/November to April/May of the following year.

On Rotten Tomatoes, the series holds a 73% approval rating, with critics praising Perry Mattfeld's performance while criticizing the show's reliance on mystery tropes and its questionable handling of physical disability representation.