The world wasn't quite sure about Steve McQueen before Bullitt. Sure, he was famous, a great actor and all that. But his best work was ensemble pictures (The Great Escape, The Magnificent Seven). Could he really carry a film on his own. There were a few good movies. Bullitt is the great movie that turned him from movie star to icon.
Frank Bullitt (McQueen) has been plucked by a political wannabe (Robert Vaughn) to guard his witness. The problem is that the witness gets shot and killed under Bullitt's watch and now he wants to know who did it and why. That's the basic story. Simple, yet complicated as the film progresses. A little too complicated. I'm not going to lie, the script isn't that great. It's McQueen and that damn car chase that makes this movie so good.
This is McQueen's defining role. Hell, we've got him selling new Mustangs on TV because of Bullitt. He was cool to begin with, but Bullitt made him uber-cool. And he sold a shitload of Mustangs with it. He maintains the movie and rises miles above a script that would be a bottom of the barrel affair with most other actors. McQueen fleshes out the film because he can. He creates something on screen that you can't put your finger on, but damn it, you know it's there.
Of course there's the car chase. Often ripped off, but never duplicated mainly because of the kick ass cars doing the chase (Bullitt's Mustang and the bad guy's Charger). I can't forget the white Firebird (the Trans-Am wouldn't show up for another year)they pass three times and the green VW Bug they pass at least six times. Sure, there are continuity errors in the chase, but who cares. It's spectacular. Just like Ned Beatty's pig scene and the surprise in the Crying Game, you've all heard of the chase in Bullitt.
That's the funny thing about Bullitt. It's such a horrible script when you think about it, but the McQueen factor raises it to classic status even above the stink of the writing. It's rare that an actor and director (Peter Yates) can elevate a movie beyond the anchor that is its script, but these two accomplish it with such a great movie that it's amazing. A true piece of late '60's film making that created the genre of the anti-hero cop that would later be defined by Eastwood and ripped off by everyone (including John Wayne himself). This is one of those true classic films.