Clark Gregg: The thread that connects 'The Avengers'

Often described as an "Easter egg" character, Agent Phil Coulson is the SHIELD agent who has popped up in many an "Avengers" movie – starting with the first "Iron Man" in 2008 – to move the plot along. Now, not unlike so-called minor characters like "Star Wars'" Boba Fett, fans can't seem to get enough of him.

In the original "Iron Man" movie, Agent Coulson served as Tony Stark's first introduction to the secretive organization, SHIELD. He was unassuming, in a suit. His role didn't demand running around in a red and yellow suit (or sporting a flashy eye patch like Samuel L. Jackson's Nick Fury). He simply informed Tony, for the first time, that he was not alone – there are more superheroes out there (laying the groundwork for "Thor" and "Captain America," not to mention "Iron Man 2").

Agent Coulson is played by character actor Clark Gregg. He'll return in 2012's "The Avengers" movie as Coulson, following the character's biggest role to date in this year's "Thor" (released on DVD and Blu-Ray this week). In total, he has shot four Marvel Studios movies.

Coulson has attempted to rein in Iron Man when necessary, and, in "Thor," took charge of the investigation into his – and his hammer's – sudden appearance on earth.

"I think the reason audiences have responded so positively to [Coulson] is that he represents the audience," said Chris Burns, who produces a series of superhero parody shorts called "Avengers Assemble," (in which he also plays the character Hawkeye).

"Agent Coulson is discovering these new people and beings along with the audience and he is going along for the ride with the audience."

Gregg (who has been married to actress Jennifer Grey since 2001) had some inkling that his character might continue beyond "Iron Man," but didn't necessarily believe it would happen.

"When they tell you, 'Oh yes, we’re gonna have you in the sequel,' so often they just don’t, and you think ‘yeah, yeah I’ll believe you when I get the call, and even then, I won’t believe you til I’m standing there,’ he said. "But in the case of Marvel, they really have been true to their word, and they really have made Coulson the gift that keeps on giving."

In the middle of shooting "Iron Man 2," Gregg first learned that his character was going to New Mexico where Thor's hammer first appeared, which would lead to his role in that film.

"They found a way to incorporate Coulson into this world. He still had this dry sense of humor but he was more in charge in this particular hammer-discovering incident," he said.

"Agent Coulson has been used as a bridge between the separate characters of 'The Avengers' movies ever since 'Iron Man,'" said Jim Littler of "And now, I think fans get all tingly whenever he appears. Plus, Clark Gregg has been an excellent promoter of comic book movies, and fans get enthused to support actors who show the proper respect to their medium."

Gregg got the ultimate invitation to the "Avengers" movie at last year's San Diego Comic-Con - from director Joss Whedon himself.

"The fact that he has written great stuff for Agent Coulson to do, with the Avengers, I would have loved (Whedon) anyway. But then when I got there and got to hang out and play with him... he’s so my kinda guy. Just fun and funny. And right out there. And vulnerable. I really had a blast working with him. One thing that was fun about this was that I got to play Agent Coulson in different worlds, different pictures. Really different directors. And I’ve gotta say Marvel’s just hit it out of the park with hiring different directors that I’ve really loved working with.”

Comic book fans have been looking forward to "The Avengers" as the culmination of the past three years in this series of films. "There is nothing like it to compare it to, except maybe the 'Harry Potter' franchise, and we all know how successful and lucrative that was," said Littler.

In the meantime, one can get their fill of Agent Coulson in quite a few other places, like the upcoming animated series, "Ultimate Spider-Man."

“I’ve been doing it for a couple of months already. [The show has] younger superheroes hiding out at a high school and the man they send to keep an eye on them is Agent Coulson who masquerades as 'Principal Coulson'," he said.

Coulson is also the star of a series of short films on DVDs of "Thor" (and "Captain America" in the near future).

Burns described Coulson as the representative of the "everyman" in "The Avengers" world. "In a normal world, he would be an exceptional agent on par with 007, but in this universe, we get to see how a non-superpowered human at the peak of covert training deals with superpowered threats and dangers."

Burns said Gregg deserves credit for portraying "a character that is accessible to audiences with out ever being condescending."

"Through it all, he generally keeps his cool and even approaches much of these fantastic events and beings with good humor and level-headedness," said Van Plexico of the fansite "That's enjoyable to watch on screen. Sometimes it's more fun to watch a 'normal' character interact with a 'super' character, than it is to watch the 'super' character by themselves."