When veteran actor Clark Gregg was cast as Agent Phil Coulson in the first Iron Man film, he was thrilled to help bring one of his favorite childhood comics to the big screen. As Tony Stark was tearing his way through bad guys, Agent Coulson was the ultimate buzz kill—the dark-suited bureaucrat trying to control the new hero. He popped up again in Iron Man 2 and Thor.
Agent Coulson may not have any superpowers, but he plays a critical role in The Avengers, recruiting a superhero squad to save Earth. On the eve of the film’s U.S. release, Gregg talks to TIME about the little role that kept growing, superhero egos and the genius of Joss Whedon.
How have you seen Agent Coulson evolve since the first Iron Man?
In Iron Man, Agent Coulson is an annoying bureaucrat. He pesters Tony Stark for an interview, tells him what to do in the press conference and identifies the Strategic Homeland Intervention Logistics Division is actually S.H.I.E.L.D.—which, as a comic book fan, is one of the many moments that Marvel has given me where I had to sit down and steady my heart as I read those pages. If you know anything about it, you know that S.H.I.E.L.D. means we’re heading for The Avengers.
This kind of thing had never been done before in film—getting the audience connected to each of the individual characters and trying to bring them together. A lot of times it doesn’t work, but when I read the script and saw how magnificently it bought them all together in one story, I was pretty blown away to be a part of it.
(READ: TIME’s review of The Avengers)
Were you an Avengers fan growing up?
I was an Ironman fan. It was in the ’70s. I definitely liked comics and drew a lot of panels on my notebook when I should have been studying—probably why I ended up in the arts. When I knew Jon Favreau was putting together this incredible cast to do Iron Man, which people forget is not a well-known character on par with the likes of Spiderman or Superman, everyone was like ‘Wow, what are they doing?’ And then when they cast Robert Downey, Jr., I was excited. They gave me a small part as Agent Coulson, who wasn’t in the comics and didn’t do much, but I jumped on it because I wanted to be a part of the movies. And when they made him the face of S.H.I.E.L.D….it was a little bit like I was the guy at Comic Con who won the golden ticket.
Agent Coulson has often been the grown-up in the room. With all of the superhero egos in in The Avengers, does he have to keep people in line ?
What I love about this character is he is always trying to wrangle these diva rock stars in spandex. But he’s not afraid to throw down some snarky lines—I have some very funny stuff to say. He is also very much with the audience, among these superheros. When the Avengers need to be assembled, he is the one who gets them all together.
(MORE: TIME’s review of Thor)
We loved Mike Casper on The West Wing. You worked with one of the great masters of dialogue in that role. What was it like to work with Joss Whedon, who is also known for creating his own language within his own world?
Funny how they are separated by 10 years because Casper, like Coulson, was originally a peripheral character. Aaron Sorkin kind of slipped him in in key moments when the FBI was needed. That made him a memorable character. Joss Whedon and all the writers of Iron Man and Thor found a way to keep Coulson saying something that keeps you guessing. I’m really lucky because a lot of people play agents and don’t get nearly as much fun stuff to do.
Because the previous films were such successes, was there a lot of pressure to make this one bigger and better?
It’s been really interesting for me—as someone who loves movies and writes them sometimes—to have a front-row seat to Marvel’s build-up for this movie. You have to remember, if one or two of the prior movies hadn’t done well, I doubt we would have gotten the opportunity to create this one. The technology actually seemed to come at just the right time to make the Hulk—Mark Ruffalo was really able to play both characters. I don’t think he could have done that a year ago.
No spoilers, please, but are we going to see more of Agent Coulson?
One thing that’s clear about the Marvel universe is that they love to keep you guessing—and when I say ‘you’, I mean me. The only thing I will add: One of the funnest things has been seeing the film with my wife—who is not a superhero fan—and watching her gasp. The Avengers is exciting on the level The Matrix or Indiana Jones was when I was kid. I think it will be timeless.
LIST: TIME’s Top 10 Superhero Movies