Over the near-decade it took to bring “The Most Hated Woman in America” to the screen, co-writer/director Tommy O’Haver would occasionally let his mind wander while reading the news to ponder what his subject, Madalyn Murray O’ Hair, the fiery atheist activist, would do if she were still around.

“That county clerk Kim Davis, I mean that was a fascinating thing,” O’Haver says of the Kentucky county clerk who defied the law in refusing to issue marriage licenses to same-sex couples. “I thought if Madalyn were here to witness that, she would’ve been down at that courthouse screaming her head off.”

Though her many foes may have thought she had been silenced for good when she was murdered in 1995, the reverberations of O’Hair’s voice carry to this day, having successfully challenged the legality of school prayer in public schools in 1963 and befitting of her way of finding her way to the biggest loudspeaker, it is all too apt that the story of her life has premiered on Netflix, especially in highly politicized times. A favorite of talk show hosts such as Johnny Carson for having a personality as big as her contempt for organized religion’s encroachment on American life, O’Hair rose from a Catholic upbringing in Baltimore to found the nonprofit American Atheists based in Austin, Texas after learning her first son Bill is required to start his school day with a prayer.

That Bill would later go on to become a minister and leader of the Religious Freedom Coalition is one of the many contradictions that makes “The Most Hated Woman in America” so intriguing and perhaps why O’Haver was such a perfect fit for the material, given his eclectic filmography. Having started his career with frothy comedies such as “Billy’s Hollywood Screen Kiss,” “Get Over It” and “Ella Enchanted,” he took a turn for much darker territory with “An American Crime,” the incredibly disturbing true story of Gertrude Baniszewski, an Indiana woman who enslaved the teenage Sylvia Likens in her basement and invited people from the community to indulge in Likens’ torture. In “The Most Hated Woman in America,” O’Haver and co-writer Irene Turner once again probe what makes a monster in investigating the sadistic streak of those who come to kidnap O’Hair (Melissa Leo), her younger son Garth (Michael Chernus) and her granddaughter Robin (Juno Temple), but asks also whether O’Hair may have struck a deal with the devil long before as she counters the hypocrisy of the religious right in finding the profit motive in her own Atheist movement, becoming every bit as effective rhetorically as any pastor preaching to the choir in building her own flock.

O’Haver and Turner make the most out of O’Hair’s wickedly funny gift for gab, as does Leo, who plays the activist over four decades, and “The Most Hated Woman in America” flourishes as an entertaining yarn, distinctly American in its celebration of our fascination with eccentricities as it is in surveying the ongoing tensions in a country founded on the principles of a division between church and state. After a successful premiere recently in Austin at SXSW, O’Haver spoke about taking advantage of the dualities in O’Hair to make such a compelling film as well as telling a story over such a long span of time in just an hour-and-a-half and blending skills he learned during the early part of his career with those he’s learned in later years.

Melissa Leo and Peter Fonda in "The Most Hated Woman in America"How did Madalyn Murray O’Hair draw your interest?

It’s funny because neither Irene [Turner] or I knew that much about her. Elizabeth Banks and Max Handelman, her husband and producing partner, had seen “An American Crime” and they approached us, looking to adapt this story. They referred us to some articles and books and we dove in. Of course, it was such an amazing story on so many different levels. The true crime aspect was a good hook, but it also had just this amazing character at the center of it, Madalyn Murray O’Hair, who had been forgotten by a lot of the world. It seemed not only the world needed to be reminded of who this woman was, but she was also amazingly complex and fascinating character to write.

I suspect I’m in a small minority who loves all your films equally – am I wrong to think this actually blended all your interests in terms of doing a story that’s both quite dark and serious at times, but also comedic at others?

Definitely, because “American Crime” was so heavy and so serious and I’m very proud of it, but a lot of people are very turned off, so it was nice to do something that actually could have a little bit of humor in it, even though it’s still pretty dark by the end. It was great to have the opportunity to flex both of those muscles at the same time.

Taking this turn towards true crime stories, how did you come to collaborate with your co-writer Irene Turner?

We went to USC together and she had produced a couple shorts for me [there] and then when I started “Billy’s Hollywood Screen Kiss,” she produced that with a couple other people. Then I had finished “Ella Enchanted” and was wanting to work on this story for “An American Crime,” which was this true crime I had known about since high school. I started to write it, but it was very scary stuff because I had never written anything like that and at the time, Irene had been writing some stuff, so I said, “Hey, would you want to partner up with me on this?” She said yes and it turned out pretty good.

Melissa Leo, Michael Chernus, Peter Fonda and Juno Temple in "The Most Hated Woman in America"Even though they’re very different stories, did making “An American Crime” influence how you approached “The Most Hated Woman in America”?

Probably yes in the sense that you’re always looking to something like this and trying to answer how or why this could happen, and with a character like Madalyn, why does she do what she does? People in general are fascinating, but when you get someone extra fascinating, whether that be a murderous mother like Gertrude Baniszewski in “An American Crime” or a political dynamo mother who wasn’t always so great to her kids in this film, it’s always great to try to figure out who those people are.

One of the things I loved in “The Most Hated Woman in America” is how the contradictions inherent in Madalyn are ingrained into the language she uses — she’s fighting against prayer in school, but will freely use “Hallelujah” to express joy. Did that come naturally?

That’s really what Madalyn Murray O’Hair was like. Quite a few of the zingers [in the film] came straight from Madalyn. She was really interesting figure that was full of contradictions and that’s what really drew us to the material in the first place, so that came pretty naturally because that’s really the way she talked and acted. She loved to stir things up, but there’s a part of her that was really a very caring person who really, more than anything, loved her family.

What was it like working with Melissa Leo on a role that covers this much time and just finding her in the first place?

She came on pretty early. I had seen her in “The Fighter” and thought oh my God, that could be my Madalyn Murray O’Hair, so I had approached her with the script and she liked it immediately. Lucky for me, she stuck with it all these years as we were trying to find financing because it is not easy to find financing for a film about a murdered atheist. [laughs] It all happened so quickly [when it did come together]. We didn’t have a very big budget for this, so we had to be very judicious about how we aged her and keeping it as simple as possible. But she just really inhabited that character. I don’t know how to explain it, but I feel like when I watch the movie, I never see her acting. She just is Madalyn.

Sally Kirkland and Melissa Leo in "The Most Hated Woman in America"Were you were able to shoot this in chronological order or did you have to jump around a lot?

We shot it in 18 days, so it was insane because it was extremely ambitious for the schedule and the amount of money we had. We had to jump around a lot because you just don’t have the luxury of being able to organize it in sequence, but we did do all the hotel stuff [which frames the film] towards the end, and once we were on the stage to do the hotel room stuff, that was pretty much in sequence. There were some days where Melissa was having to play two or three different ages in a day. It was a crazy schedule.

Visually, something I appreciated was how you showed Madalyn’s radicalization – did you actually intend for her costumes to blend into the background as she was still living in Baltimore?

That’s interesting – I never thought that much about it, but a lot of those costumes are based on the way she was dressed at certain times in her life, so in reality her style evolved in that direction, so that’s just a byproduct of looking at photos of her through the years and trying to capture the spirit of those photos in the film itself.

What was the premiere at SXSW like for you?

It was great because so much of the film takes place in Austin and San Antonio, so it seemed to be like the perfect place to premiere it. The last time I had been in Austin was actually with Irene when we did some research and check out some of the nooks and crannies of Madalyn’s life there, so it was great to return with the film itself.

“The Most Hated Woman in America” is now streaming on Netflix.