Legendary director William Friedkin spent last weekend at the Harvard Film Archive.

Over the course of his long, storied and often erratic career, this poet of masculine brutality helmed confrontational, exceedingly unpleasant masterworks like The French Connection, The Exorcist, Sorcerer, Cruising and To Live and Die in L.A., before languishing for too long within the Hollywood studio system, churning out a lot of pictures that are probably best left unmentioned. (Let’s not talk about Jade and The Guardian, okay?)

He mostly directs opera these days. But Friedkin’s third-act cinematic resurrection was sparked by playwright Tracy Letts. Their simpatico sicko sensibilities brought us 2006’s Bug and 2012’s magnificent Killer Joe. Shot independently on shoestrings, far away from meddlesome executives, these hyperbolically rotten, ghoulishly mordant, close-quartered theatre adaptations reveal a director who no longer gives a fuck what anyone else thinks.

The 79-year-old filmmaker has never seemed so young, and the films feel electric and alive again. After mock-apologizing in his introduction for what we were about to see, Friedkin spoke for over an hour with the shell-shocked Harvard audience after a screening of his boastfully NC-17 Killer Joe. Here are some edited highlights from that discussion:

On how a renowned, Academy Award-winning director got mixed up with this filthy little low-budget, rotgut noir…

Well The Exorcist was purely about the mystery of faith, and God knows what this is about.

Tracy Letts actually read about a case like this in the newspaper. It occurred in Florida, somewhere. A family hired a hitman to kill their mother for the insurance policy. Tracy was drinking a lot at the time that he wrote this. He was drunk most of the time and he wrote this under medicinal care, as you can probably gather. I still find it tremendously humorous. I love the way Tracy Letts writes, that’s what drew me to this. He and I have the same worldview, sick as it may be.

I have no idea what goes through my mind. None. I get an instinct about something when I read it. I have to see the film in my mind’s eye or I don’t know how to do it. I see the whole film. I saw this film in my head before I started to direct it. I knew instinctively where all the shots would be. I don’t do storyboards.

What draws me to a film like this, I have no idea. I could make The Waltons if somebody asked me to, but I have no interest in doing so. I will share with you that my own family was very close. I never had any problems with my mother and father. I don’t have any of this. Through all of my films I’m basically an observer, an interested bystander.

I don’t know if you ever ride the subways or the elevated trains, but I do often. Just listen to conversations that occur around you. I’m curious in that way, and that leads me to the kind of material that I’m drawn to. Human behavior. The proper study of mankind, that’s what all my films are about. Even though a lot of the characters are hateful, malicious without any validating circumstances, I’m interested in human behavior. That’s what makes me want to be a director, I’m drawn to films where human behavior is portrayed at its extremes. And Killer Joe is certainly an extreme of human behavior.

I do believe that there is good and evil in every human being who ever lived, including Mother Teresa, Jesus and Hitler. I believe there is good and evil in every single one of us and that it’s a constant struggle for our better angels to thrive over our demons. I know there’s good and evil within me. I often have evil and negative impulses, and I constantly try to not give into them. Sometimes I’m not successful. All of that comes out in the films that I make.

On translating Letts’ single-set plays to the differing demands of a big screen…

It’s a challenge. It’s claustrophobic, and I think claustrophobia produces a lot of interesting tensions and emotions. Claustrophobia is one of the things I’m fascinated by — people who have their backs to the wall and no escape. They can’t get out. And it’s usually one room, like the Jean-Paul Sartre play No Exit. Most of the characters in the films I’ve made are in a No Exit situation. I’m drawn to works like that. Everything here was on the page and I just moved the camera around as much as I thought was reasonable. I wanted to put the audience in that trailer, and at that table.

The way I approach it, and if someone were to analyze my films shot-by-shot and frame-for-frame, you’ll see what I have attempted to do – and not been totally successful in doing it – I have emulated the films of Antonioni, who never repeated a set-up. In most films that you see there’s a wide shot, then an over-the-shoulder shot of one of the people, and then a reverse over-the-shoulder shot, maybe a couple of close-ups, and the director will go back and forth.

You can almost sit there, watch a movie and know where the next cut is gonna come. I’ve done this, I’ve sat there and gone (snaps finger) then they make the cut. And you know it’s gonna be over-the-shoulder, over-the-shoulder, single, two-shot, single, two-shot. I don’t do that.

Antonioni would do a hundred straight shots or more without repeating a set-up like that, so his films –even though some of them are very slow– they seem to move laterally. It’s as though you’re reading a book, the way you scan a book from left to right… unless you’re reading Hebrew. That’s how an Antonioni film plays, it sort of scans and moves along laterally instead of going back and forth and back and forth.

That’s how I planned the set-ups for something like Killer Joe and Bug. I would try never to repeat a shot.

I wasn’t always successful, because you always have to go with the performance. Even if that means repeating a shot, because the performance is so good in something that you are forced into a repetition. But otherwise, I try. And the more films that I’ll make, by the grace of God, I will try even more to never repeat a set-up, so that the film will move like you’re scanning the pages of a book.

On directing Matthew McConaughey and Gina Gershon in Killer Joe’s appalling, notorious fried chicken finale…

Was there any discomfort? Yes! My direction was:  “Are you guys ready? Let’s do it.” I shot it with multiple cameras in one take. They knew if they got it right once they wouldn’t have to do it again. Neither one of them enjoyed doing it, nor did I enjoy watching it. I thought it was one of the sickest things I’ve ever seen… but I didn’t tell that to the actors.

What a lot of directors ask actors to do is to apply sense memory. The Stanislavski method of acting is based on sense memory, in order to portray an emotion you have to search your memory and find that moment when you were sad to play sad, or happy to play happy — whatever the emotion might be. I used that a lot with Linda Blair in The Exorcist. She was twelve when she made the film, and I asked her about times that upset her, what would make her cry or be scared, and she would tell me.

You know, I get very close to the actors, it’s almost like psychology — not psychiatry because I’m not trying to help them or cure them — but I try to learn what produces those emotions and then I will make certain subtle hints for their performance.

It was impossible to do that with a woman sucking on a chicken bone. But I did ask Gina Gershon to remember times when she felt most humiliated, and those times ran through her mind when she was doing the scene.

And on the gloriously obscene, hilariously incongruous closing credits track…

I’ve been listening to Clarence Carter for years, and I was always hoping to be able to use “Strokin’” in a movie. “Strokin’” is one of the great American songs. To me, he was the Mozart of Southern music. You can almost never hear “Strokin’” on the radio, not in this politically correct world. So I thought I should give this to the audience — it has nothing to do with the picture.

There’s a disc jockey in all of us, and I just wanted to share “Strokin’” with all of you. Why not? Where are you gonna go and hear “Strokin’” in this day and age? Where? Nowhere! Here, that’s it!

I mean, if I were doing a movie about the life of Beethoven, I would use “Strokin’” on the end credits. Or Shakespeare! You know, if I was doing Hamlet, imagine ending it after Hamlet’s death, and the funeral oration by Horatio or Fortinbras, then you hear “Strokin’.”  And that sends you right out of your chair – YES! It’s not about a guy who got killed in a duel, and killed his uncle because his father’s ghost told him that his uncle was sleeping with his mother and he had to kill his uncle… what a stupid plotline that is.

Now if you end it with “Strokin’” you have a whole other kettle of fish. The audience goes out bopping. Strokin’.