Gyllenhaal stars as Lou Bloom, an unscrupulous drifter who weasels his way into the cutthroat world of news gathering.
Success at any cost
The movie, by veteran screenwriter and first-time director Dan Gilroy, also paints an unsettling picture of L.A.'s seedy underbelly.
Gyllenhaal, who also produced the film, admits Nightcrawler is taking a calulated jab at the chew 'em up, and spit 'em out media landscape.
"There's definitely some political subversity here," he told CBC Arts.
"This movie is a comment, in a lot of ways, on the current state of the media," Gyllenhaal said. "There is some part of my culture that has said to me 'success, almost, at any cost.'"
The filmmaker will see if he has a box office success on his hands when Nightcrawler goes into wide release on Oct. 31.
The Toronto International Film Festival runs through Sept. 14.