One of America’s most intriguing officials lived a life destined to reach the big screen. The story of former FBI Director J. Edgar Hoover is being tackled by legendary filmmaker Clint Eastwood with a portrayal by Leonardo DiCaprio in the upcoming biopic J. Edgar.

At CinemaCon, Warner Bros. gave a quick sneak peek of DiCaprio as Hoover – and it was an impressive 30 seconds.

In the midst of an extensive sizzle reel promoting Warner Bros.’ upcoming slate of films, a small bit of J. Edgar was put on display. It was a simple scene – DiCaprio as Hoover giving an impassioned speech to Congress. It was a single shot, slowly rising and approaching DiCaprio. Yet, in all this simplicity was evidence that DiCaprio has completely embodied the enigmatic FBI Director in what might be Clint Eastwood’s best film in some time.

That’s quite a lot to say after only seeing 30 seconds, and it is meant to be taken with a grain of salt. Unforgiven is a true classic and Million Dollar Baby did win Best Picture, but few characters are so wonderfully engaging as J. Edgar Hoover. The charismatic character exudes an intensity few figures in history can challenge. While much of his personal controversy came later in life, there is plenty to tackle in the early years.

DiCaprio on set as J. Edgar Hoover (via SplashNews)

The clip shown at CinemaCon was quick, but intense. It grabbed attention with force and immediately sucked the audience in – maybe that was all DiCaprio. The scene showed Hoover testifying before Congress in regards to the proposed National Fingerprint Database.

“Bring all the fingerprints in this country to my office so that we may create a central file to help arm our agents so that they may have a fighting chance against the sub-machine guns of some of the most dangerous characters in the history of American criminality. And I urge you to do this in the name of little Lindy, because if he can be taken, then what child is safe? … If we cannot aid in his safe return, then what use are we?”

It may be difficult to read that with no reference and believe it was engaging, but it was. As mentioned, DiCaprio has captured the personality of Hoover. After all, this is the actor who has already brilliantly portrayed (brilliantly) real-life characters like Howard Hughes (the Aviator) and Frank Abagnale, Jr. (Catch Me If You Can). Many other characters exist within fictionalized true stories and he continues to shine in those instances. It is clear DiCaprio is at his best when he has something real to latch onto.

One note on the performance was his accent. Hoover had a very distinct accent and deliberate speech pattern. While it was jarring to hear DiCaprio at first, it grew on me rather quickly. In the context of an entire film, it should be easier to listen to, but just like Blood Diamond, some audience members will, undoubtedly, complain. Frankly speaking, Hoover didn’t talk in a fashion that movie fans would enjoy. He was quick, intense, passionate and long-winded – which makes for great moments like the one we saw at CinemaCon.

clint eastwood directs hoover biopic CinemaCon: First Look at Leonardo DiCaprio as Hoover

Hoover’s past is ironically quite mysterious. As the leader of the nation’s first truly effective investigative system, he found a way to completely control the public perception of his lifestyle and his personal motivations have always been held under major scrutiny. The big question actually is the man he promoted to the public. Among other reasons, this is one aspect of the biopic that should make it especially compelling.

Looking at the big picture, biopics are tough. It is easy to focus on one segment of a particular life, but from the sound of it Eastwood will attack the larger scope of Hoover’s life. DiCaprio and writer Dustin Lance Black have also confirmed that the cross-dressing antics and rumored homosexual tendencies of Hoover will be explored. The complexities of the man’s personality will make for a film that is layered and textured, but could make it especially difficult to keep focused.

J. Edgar Hoover has reached the big screen on a number of occasions. The most difficult challenge, for DiCaprio and Company, is creating a film that is not only true to its character, but engaging and entertaining – beyond the headline antics of Hoover’s controversial side.

What do you think of the upcoming biopic? Do you need to see more to get behind it or are you excited to see DiCaprio and Eastwood team up on the big screen?

J. Edgar looks to reach theaters by late 2011.