The movie The Last Kiss was a failure at the box office this weekend, but its headliner, Scrubs star Zach Braff, should be dancing on the ceiling.

After several years as a charming goofball on the popular NBC series and two years after his directorial debut with Garden State, he has sunk his teeth into a role that not only profits from his affable persona but deconstructs it.

Let me put it more simply: He plays a man who does some very bad things. It made me very uncomfortable. But it’s the best acting Braff has yet done.

An excellent film that deserves better, it’s too bad not many people are bothering to see Kiss. In this case, though, the public isn’t completely to blame — it is as much the fault of Braff and the film’s marketing campaign.

Take a look at the trailer: It comes off as a story about a guy in a serious relationship with a wonderful woman who hits a patch of indecision and meets a younger girl who makes him rethink it all, a “Garden State 2: Electric Bugaloo” of sorts. The trailer fails to mention that “wonderful woman” is pregnant — a plot point, don’t worry, revealed minutes into the film — and that Braff’s character is fully aware of it as he strays.

That changes things. The Last Kiss, contrary to what its bouncy trailer conveys, is a wrenching and often profoundly sad drama that cuts to the quick of everyone’s fears about post-college life. Braff is perfect because he adds some levity but is enough of an Everyman that the anger we feel seeing him do what he does is turned inward as much as at him.

Right now, that Braff ‘R’ Us element is working against him. The 31-year-old has become a small-time indie Oprah of sorts since Garden State. His stamp of approval on a particular song or artist means something (“This song will change your life”) and his mini-legion of fans see him more as a state of mind – Braffness, we’ll call it – than an actor.

Garden State glamorized the quarter-life crisis as a happy ending around the bend and some good background music. The Last Kiss, no less redeeming in its beautiful conclusion, is far bleaker and to-the-point, but neither of those sell tickets.

Regardless, the movie represents a huge leap in the right direction for Braff. He was wise to let others do the writing and directing and as a result, the movie lacks the mawkish self-seriousness of Garden State and is deeply moving, if not hard to watch at times.

Maybe Braff expected this, because he certainly created a compromise. The soundtrack, once again, rocks.