When Jake Gyllenhaal walked onstage with his keynote talk Saturday, the anticipation amongst the audience was palpable. To them, he’s the legendary star of films such as “Donnie Darko,” “Jarhead” and “Prisoners.” He’s here to help promote his new film, “Demolition,” which premieres tonight at South by Southwest.

His interviewer was David Gordon Green, who is also the director of Gyllenhaal’s upcoming picture about Boston Marathon bombing. Green and Gyllenhaal shared an easygoing rapport, and they quickly segued into a lengthy discussion about Gyllenhaal’s acting process and experiences.

Gyllenhaal said he picks his movies based on their stories, not on the roles. For him, the important questions regarding a script are: “Do I want to move to the next scene? Do I want to find out what happens to these characters?” If the answers to those questions aren’t “yes,” then not even the most spectacular computer-generated effects matter.

“Narrative is spectacle,” he said. “Tension is everything.”

He said his admiration screenwriting came from a childhood experience where he observed the production of “Running on Empty,” a 1988 film written by his mother, Naomi Foner.

“What I saw was a deep respect for the screenplay,” Gyllenhaal said. “The writer just happened to be my mother. I have tried to carry that through.”

However, Gyllenhaal mentioned that grounded, intimate dramas aren’t the only ones that can connect with people, addressing big blockbusters like superhero films.

“I walked out of the theater after ‘Thor’ and I was actually very inspired,” he said. “There’s a reason for myth.”

In order to develop his authentic performances, Gyllenhaal said he uses his imagination and attempts to empathize with his characters, including the sociopathic Louis Bloom in “Nightcrawler” and apathetic widower Davis Mitchell in “Demolition.” He said he doesn’t feel that his stranger characters are really unhinged and shouldn’t be labeled as abnormal.

“I actually find it disturbing when you are expected to react certain ways to certain things,” he said. Because of his empathetic approach to his characters, Gyllenhaal ends up finding feelings such as apathy very relatable.

When it comes to his more demanding roles, such as the boxer Billy Hope in “Southpaw,” Gyllenhaal admitted he experiences the fear the he won’t look credible onscreen.

“First you have a little panic attack and you have to take a step back,” he said.

For his more challenging work, Gyllenhaal has to mentally prepare himself, and for his darker characters and stories, finds it a little difficult to separate the seriousness of his work from his personal life.

He also recalled “Donnie Darko” and said, “It was one of the proudest moments of my life. It’s a movie that exists where I love to be. Anyone that wants to know what’s going on in my mind, go and see that movie.”

It’s been 15 years “Donnie Darko” was released, and Gyllenhaal is still collaborating with recognized talents in Hollywood. In fact, it’s not surprising that he and Green have ended up working together.

Green said he was once mentored by Gyllenhaal’s father, director Stephen Gyllenhaal, and remembered an oddly prophetic statement he had made.

“I hope you get to make a movie with my son,” Stephen Gyllenhaal had said. “You’ll like him.”