Director Dan Gilroy originally conceived a film about American photographer Weegee in 1988 after reading his photo-book Naked City, but shelved the idea after The Public Eye (1992) was released, later reviving the concept by focusing on the modern stringer profession instead.

Gilroy struggled for years to design a compelling protagonist, studying antiheroes from films like The King of Comedy, To Die For, and The Talented Mr. Ripley before deciding to build Lou Bloom as a successful antihero rather than a psychopath who devolves.

Gilroy deliberately left out Lou Bloom's backstory so that audiences would invent their own history for the character and become more engaged with him.

Jake Gyllenhaal, who also served as a producer, lost nearly thirty pounds for the role by eating only kale salads and chewing gum while running fifteen miles a day, after Gilroy described Lou as being like a coyote driven by never-ending hunger.

Riz Ahmed was one of 75 actors who auditioned for the role of Rick, and prepared by meeting homeless people in Skid Row and researching homeless shelters to understand the system.

Dan Gilroy wrote the role of Nina specifically for his wife Rene Russo, believing she could bring vulnerability to a character that could otherwise be reduced to a stereotypical 'hard-nosed corporate bitch'.

Principal photography lasted only 27 days across 80 different locations in Los Angeles, with the crew often having to move to multiple sites each night and never finishing filming before sunrise.

Real-life stringers, the Raishbrook brothers, provided licensed background footage for the newsroom scenes and served as technical advisers; Gilroy, Gyllenhaal, and Ahmed even rode along with them at night to accurately portray the stringer lifestyle.

Composer James Newton Howard departed from his usual large cinematic scores to create moody 1980s-influenced electronica, using triumphant-sounding music during dark scenes—such as when Lou moves a dead body for a better shot—to convey the excitement inside Lou's mind.

Open Road Films promoted the film with viral marketing, including a fictional video résumé for Lou Bloom posted on Craigslist and fake LinkedIn and Twitter profiles promoting his supposed video production business.

An unfinished cut of Nightcrawler screened at the 2014 Cannes Film Festival sparked a bidding war among distributors including A24, Focus Features, Fox Searchlight, and The Weinstein Company, with Open Road Films acquiring U.S. rights for around $4.5 million.