Plus, you know, there’s Steve McQueen.

A mercurial person on set and in his personal life, with a set of experiences that contains everything from the Marine Corps to Charles Manson, from starring in a film with the real-life “Emmanuelle” to throwing beer cans into neat freak James Garner’s driveway, McQueen became and still remains perhaps the quintessential icon of American cool. Few celebrities managed to maintain their sense of cool across so many shifts in public taste. Whether sporting a three-piece suit or a white t-shirt, a roll-neck sweater, a Mackintosh, or racing coveralls, McQueen seemed to effortlessly pull off classic American style, something he doubtless put considerable effort into. He made formal wear seem laid back and casual wear seem formal and whether in one or the other, never seemed sloppy or lazily presented. Whatever demons plagued him in life – and he certainly had them – they took a back seat to the image.

For his role as a slightly embittered but still dedicated police inspector in Bullitt, McQueen tagged along with real-life San Francisco cop Dave Toschi. Toschi, reportedly also the basis for Clint Eastwood’s later iconic cop on the edge “Dirty” Harry Callahan, rose to national prominence as the lead investigator on the infamous Zodiac killings, a series of murders that took place in San Francisco between December 1968 and October 1969. McQueen didn’t pick Toschi as his model because of the Zodiac killings (they had yet to happen), but rather because the investigator was already well-known in the city. In particular, McQueen copied the unique “upside down” quickdraw shoulder holster that Toschi wore. He did not, however, copy Toshi’s fondness for wearing a large bow tie with a short sleeve button-up shirt, though I have no doubt McQueen would have some way managed to make it work. Instead, McQueen opted for a look that would become one of the most iconic of the actor’s career: a dark blue rollneck sweater, brown sports jacket, and tan Mackintosh.

The film opens with a shoot-out that sees an unknown thief helping himself to something in a law office then trying to sneak past a gauntlet of armed assailants scattered throughout the office complex and adjoining parking garage. Cut then to Frank Bullitt, sleeping off a bender when he’s rudely awoken in the early afternoon and dragged off to receive his latest assignment: protecting a witness against the Mob, who has fled to San Francisco after stealing incriminating evidence in Chicago (the heist/shoot-out from the beginning of the movie). The informant, Ross (Felice Orlandi), is the star witness for politician Walter Chalmers (Robert Vaughn), who plans to parade Ross in front of Congress during some hearings on organized crime. Bullitt’s job is simple: keep Ross alive until he can testify. Unfortunately, Chalmers has picked a seedy, run-down hotel with cheap doors and too many windows as the safe house. No one should be surprised when gunmen manage to infiltrate this less-than-a-fortress and shotgun the witness in the face, blasting a cop in the leg during the melee. what makes less sense is Ross’ apparent complicity in his own attempted murder.

Ross, it turns out, isn’t dead, but he’s pretty close, and while Chalmers comes down on Bullitt, Bullitt’s focus shifts to finding the trigger man, who he hopes will lead him to a boss. A subsequent attempt on Ross’ life in the hospital, and the fact that the hitmen knew where to find Ross in the first place, raises Bullitt’s suspicions even further. He keeps his cards close to the vest, infuriating Chalmers. The remainder of the film is largely a procedural that succeeds because of McQueen’s onscreen charisma and an attention to detail that was still relatively new in cinema.

Director Peter Yates and Steve McQueen(whose own company produced the film), working with Harry Kleiner’s 1963 novel Mute Witness as their source material, aimed for an unparalleled degree of realism both for police as well as hospital procedure, opting at times for an almost documentary style of filmmaking that dwelt on the nitty gritty of cop work and emergency surgery. They also shot the film more or less entirely on location on the streets of San Francisco rather than relying on sets and sound stages. Just compare their San Francisco to the San Francisco of a decade before in Hitchcock’s Vertigo, which used locations for establishing shots but was predominantly reliant on sets and matte paintings.

This approach to filmmaking would come to typify film in the 1970s, where the authenticity of the streets was as important a character in the film as the characters themselves. A lot of Bullitt is just Bullitt following leads and just pounding the pavement in and around San Francisco, turning the film into a snapshot of the Bay Area in the late 1960s, stripped of most of the costuming and artifice that might otherwise appear in a film set in the same area. Landmarks make appearances (how can you not show the Golden Gate Bridge, after all), but by and large this is San Francisco from a resident’s eye view: corner stores and newspaper stands, grocery shopping and waiting at stop lights. If the pacing of the film ever seems to flag, it’s usually buoyed by the streetwise scenery.

That assumes, of course, one thinks the pacing ever flags, which it doesn’t. Frank Bullitt’s investigation gets increasingly complex as the threads he follows become more and more tangled. At times it’s almost impossible to sort out exactly what’s happening, though it all gets sewn up in the end. Like a classic film noir, Bullitt walks viewers through a labyrinth of crime and suspects before finally coming out the other side. While not everything ends up making sense, it’s all still interesting. In between are a few exquisitely realized action set pieces. The first, the car chase up and down the hilly streets of San Francisco, has become the stuff of cinema legend for good reason.

Executed on actual San Francisco streets, with McQueen doing much of his own driving (the riskiest bits were done by stunt driver Loren Janes, a frequent McQueen collaborator), it’s the textbook example of how to shoot an urban car chase. While McQueen and Janes piloted the film’s signature green Mustang, Bill Hickman drove the Dodge Charger and, for the sake of simplicity, was simply cast as the hitman who eventually winds up behind that wheel.The steep streets of San Francisco turn the whole thing into a roller coaster. At this point, there is no McQueen; there is no duo of shadowy hitmen. The only characters in the movie are a Mustang, a Charger, and San Francisco’s streets. The sequence was coordinated by Carey Loftin and won editor Frank Keller an Oscar (despite the somewhat famous continuity error of the frequently reappearing VW Bug, which occurred because the scene wasn’t assembled int he same order it was shot). The chase doesn’t boast much in the way of pinpoint precision like viewers would get in, say, The Italian Job (released a year later in 1969). These are American muscle cars, after all; they’re not known for their grace and handling. But muscle – boy does it have that in spades.

The second big action scene comes during the film’s finale, during which the complicated plot has finally been more or less deciphered. Bullitt chases his quarry across the busy runways of San Francisco’s airport, and later through the airport itself. If the choreography of the car chase is obviously intense, the choreography during this final foot chase is no less impressive despite being discussed less – because this one involves people running in front of, behind, and under actual moving jets. A few other tense foot chases and shoot-outs peppered throughout the film keep everything moving at a brisk clip even when the film settles down. It’s a great example of the economy of action, of how to use it exactly when you need it to make things thrilling, instead of just jamming so much in that it becomes tedious, as can often be the case with action films of a more recent vintage.

Although not overtly a political film, Bullitt manages to slip in a few surprising moments of social awareness reflective of current events. Robert Vaughn’s Chalmers isn’t a typical corrupt politician, but he is self-serving and egotistical, more than willing to put questionable pressure on people to get his way. But the film’s most telling scene comes when Ross and the cop Stanton (Carl Reindel) are whisked away to a hospital after the motel shooting. The doctor operating on them, Dr. Willard (Georg Stanford Brown), happens to be black, a situation that makes Chalmers uncomfortable. When Bullitt and the doctor overhearing Chalmers demand a different doctor be assigned to Ross (someone a little…more professional; older, you know), Bullitt and the doctor share an exasperated glance (which turns into a willingness on the part of the doctor to help Bullitt). Brown’s isn’t a large role, but he’s good in it, and the moment that passes between him and Bullitt speaks volumes. The simple fact of Brown’s presence, playing a skilled professional and not some junkie or mugger, is enough to make Bullitt rather a more progressive film than many of its contemporaries.

The rest of the supporting cast is uniformly good. Robert Vaughn, fresh off his success in the television show The Man from U.N.C.L.E., is perfectly cast as a scheming political up-and-comer, a guy who isn’t corrupt but still manages to be a colossal jerk. Robert Duvall, still small potatoes at the time, shows up in a small role as a cabbie. The film’s only real misstep is the romantic subplot between Bullitt and his long-suffering girlfriend, played by Jacqueline Bisset (who had just appeared in the 1967 James Bond farce Casino Royale as Giovanna Goodthighs). Bisset is fine, but the entire thing is somehow both undercooked and overcooked and seems shoehorned in. She’s saddled with the film’s most obviously scripted dialogue. The bulk of what’s said elsewhere and by other characters sounds like real talking, delivered in the naturalistic style that was becoming the dominant form of acting. That she’s forced to deliver lines that sound much more scripted and in a much more formalized style sticks out like a sore thumb; not enough to mar the film in any significant way, but enough to do Bisset a disservice.

But this is Steve McQueen’s show, and he carries the film in a way that looks almost effortless. There’s no overblown drama, no moment of arch “acting.” It’s subtle, realistic. Bullitt is almost the point at which we can look at films and say this is where the old method gave way to the new. McQueen glides through the film in entirely natural fashion, never looking or sounding anything less (or more) than a cop working a shitty, confusing case. Everything that was Steve McQueen comes together in Bullitt, a film that relies heavily on his own sense of style, a meticulously crafted blend of the formal and the casual. And yet, one never feels like one is just watching Steve McQueen. You’re watching Frank Bullitt. The movie and the character is so aligned with McQueen’s image that he easily disappears into the role. They could have made a movie that was nothing but two hours of him walking around San Francisco in that rollneck and jacket, and I would have happily watched.

As is the case with many movements, revolutions, and quantum shifts, you can’t point to any one thing and say that’s where it all began. By the time Bullitt was released, we already had Bonnie and Clyde, In the Heat of the Night, The Graduate, and John Boorman’s “heist film as art film” Point Blank, all released in 1967. Bullitt didn’t start the trend that would become “the new Hollywood,” but it certainly helped cement it. Steve McQueen doesn’t often get mentioned alongside those new method actors, but in Bullitt particularly, he proves himself every inch the measure of some of the more acclaimed stuttering, mumbling stars of the era. And he brought a level of established star power to the method that was rivaled only by Marlon Brando (Pacino, De Niro, and Hoffman being newcomers at the time). On top of all that, or maybe apart from it if such things are of no concern, Bullitt is just a fantastic cop film. He may have received more acclaim for other films, but few are as essentially Steve McQueen.