Mike Flanagan described Midnight Mass as a deeply personal passion project reflecting his upbringing in the Catholic Church and his own journey toward sobriety and atheism.

Flanagan first conceived Midnight Mass as a novel, then as a film script, and unsuccessfully pitched it as a TV series to several companies, including Netflix, back in 2014.

Flanagan and Kate Siegel first adapted Midnight Mass as a story-within-a-story in their 2016 film Hush, where it is presented as the most popular novel written by Siegel's character, Maddie Young.

Flanagan kept the idea alive over the years by planting the Hush prop book titled Midnight Mass as an Easter egg in his 2017 film Gerald's Game.

Hamish Linklater plays a dual role in the series, portraying both the enigmatic new priest Father Paul Hill and the aging Monsignor Pruitt whom he temporarily replaces.

Production was originally set to begin in March 2020 but was delayed by the COVID-19 pandemic, eventually running from August 17 to December 15, 2020, in Vancouver, British Columbia.

The production built the town set for Crockett Island at Garry Point Park, a seaside public area outside Vancouver.

The score was composed by The Newton Brothers, Andy Grush and Taylor Newton Stewart, who have worked with Flanagan on every project since his 2013 film Oculus, and the soundtrack features reimagined Christian hymns alongside original compositions.

Rahul Kohli said in an interview on Michael Rosenbaum's podcast Inside of You that playing Sheriff Hassan was his most difficult role, since he is not Muslim, not American, not a father, and not forty.

Kohli's portrayal of Sheriff Hassan was praised by many Muslim viewers as a rare example of positive and accurate Muslim representation on screen, particularly a scene where he discusses religious texts in public schools.