The streets of downtown Austin are stirring blearily to life as the turducken street taco that is SXSW—a weeklong tech expo wrapped inside a film festival and finished off with a music showcase—shakes off the previous night's revelry. But backstage at the Austin Convention Center, where he is due to deliver the film festival's keynote address, director-producer-writer-actor Mark Duplass is rested and alert. His father is here, and so is his agent, and so is a tray of pastries, which Mark eyes warily.

Mark is a 38-year-old former athlete—he ran track in high school—and he possesses that strain of shticky carb anxiety common to the contemporary middle-aged male. His Twitter bio reads, "Resisting donuts, daily." On December 18 he tweeted, "I want a donut so goddamn bad my heart hurts." Tomorrow he will give an interview to Salon in which he refers to them as a source of "extreme joy" followed by intense regret: "With years of therapy, we've been able to extend that doughnut joy from the 12 seconds of eating to another three minutes before the shame." The point is, Mark is used to regulating his impulses for his own protection, and that's why he eschewed yesterday's industry parties and screenings in favor of a couple of miles on the treadmill and eight hours of sleep and why now, while the rest of the city struggles to rouse itself, he is full of energy and ready to take the stage.

Judging purely by his résumé, Mark is a fitting keynote speaker for SXSW's maximalism. As an actor, he has securely attained oh-hey-that-guy status. You might recognize him as the smirky Pete from FXX's fantasy-football comedy series The League or the competitively sensitive midwife Brendan on Fox's The Mindy Project or the tightly wound, undersexed Brett in HBO's Togetherness. But to the people filing into the auditorium, he is better known as one half of the Duplass brothers, an indie-film juggernaut that has written, directed, or had a hand in producing 24 movies over the past 19 years—including four new films screening at this very festival—not to mention Togetherness, every episode of which they wrote, produced, and directed. Beyond their prodigious output, Mark and his brother, Jay, 42, are celebrated for creating an entirely new model of DIY filmmaking, one tailor-made for the Netflix era of digital distribution. Twenty years ago every young director dreamed of becoming the next Quentin Tarantino. Today they all want to be a Duplass brother.