“She was 40 when she had me, [and] she really did sort of walk and talk like Amelia Earhart and Humphrey Bogart put together,” Mills tells Fresh Air‘s Terry Gross. “I was always trying to figure out what her deal was.”

Mills’ latest film, 20th Century Women, is inspired by that yearning. Set in Santa Barbara in 1979, it stars Annette Bening as Dorothea, a 55-year-old woman who grew up during the Depression and is struggling to raise her teenage son, Jamie, on her own.

The director acknowledges that his mother, who died in 1999, was a private person and might have been resistant to a movie about her. He says he grappled with her spirit while he was writing the film.

“My mom is a very tricky ghost,” Mills says. “At one certain point, there was a conversation with her ghost that went something like, ‘OK Mom … I’m sorry, I’m just going to do this, and I know that it’s filled with enough love and enough understanding that I feel like if I ever see you again I can defend myself — or I can deal with your ire.’ ”

Sometimes people call it a coming-of-age movie and I’m always like, “Oof, it’s a really bad coming-of-age movie, if that’s what it is,” because the kid doesn’t change, the son doesn’t transform. The son is a vehicle to see the mother and the other women, to see the Greta Gerwig character and the Elle [Fanning] character. … He’s like a catalyst. Things happen because of him, but he’s not the protagonist, he’s not who you enter.

Growing up listening to women’s experiences 

I don’t know exactly why this is, if [it’s] just because I grew up in a matriarchy, or because I grew up with these older sisters, for whatever reason, I’m often in this position of being around women who are talking to each other as if a man wasn’t there. …

I had two female friends who were very — whatever you want to call it — popular, and sexualized beyond their years, and they would go out with much more sophisticated men, boys, at night … and then my bedroom was sort of away from the house, so you could easily sneak in and out. And then around 4 in the morning they would roll by my place, get in bed with me, and talk to each other about everything that happened, and not just in a partying way, but the real struggles they were having with their sex life and with the guys they loved and didn’t love and all the complexities and I just happened to be there.

Interviewing close female friends 

As a heterosexual, cisgender guy talking about women, I was very worried and wanted to find where my limitations were and sort of make them part of the piece.

Writing

Writing is such a horribly isolating practice, I was desperate just to go and meet other people, kind of work in a slightly more journalistic way. I wanted to conduct interviews to find little nuggets of details I could insert in my story. …

Script:

It’s slightly documentary, slightly journalistic flavor to the writing practice and it gets you out of your little cell.

The beginning of my writing process is I just try to remember as much stuff as I can and write them down on single 5×7 cards. I don’t think about structure, I don’t think about Final Draft, which is the software you write scripts in, and I’m just compiling, compiling, compiling and I have a character stack and those were the Jamie stuff. …

A key thing for me in writing younger people and teenagers and especially these guys that are in my movie is not to treat them like teenagers. In their mind, they’re fully developed entities. They’re at the peak of their game. They don’t think of themselves as 14, 15 years old. They think of themselves as complete, and so I found if I just wrote as I would write myself in lots of ways, myself now, it just felt better and worked better and showing it to Elle and to the different kids I approached for Jamie, Elle really liked it, she felt it was very accurate.

Symbolism of a burning car in the opening scene

I really wanted to make a story about a fatherless home, which even though I had a dad and he was home, it was sort of a fatherless home; in terms of real emotional connection, he just wasn’t there.

So I’m trying to create this land where it’s a fatherless home, a man-less home, a boy who is being raised by women. How do I get that idea going? How do I introduce that idea to the audience? Just doing my research about that time, the late ’70s, is kind of like the beginning of the end of Detroit. The beginning and ending of the big car, and cars and Detroit and industrial America, it’s all kind of masculine masculinity, so I just sort of unconsciously, intuitively was like, “OK, the car is men, the car is dad” … and starting the film with dad’s funeral, in a way, by this car accidentally catching on fire in the parking lot.

On his film Beginners, inspired by his father, who came out when he was in his 70s

I didn’t know my dad was gay, and then he comes out when he’s 75 and he has these amazing years of just opening exploration and mess. … That mess was really helpful for me to see, and then the way he handled the way he died was just so intense and wild, and part of my grief process, whatever, was writing that script. I wouldn’t normally have done something so personal. I love it when other people do it. … I love so many authors and filmmakers who use their personal life, but I didn’t see me being brave enough to do that.

One of the weird benefits of grief is it makes you kind of unsober and your feelings are so hot and rich and alive. It’s an amazing place to write from, and it just makes you kind of braver. So that movie came out and people think … my relationship is so key with my father, which it was, especially when he came out. But the real person in my life, the real person who shaped me is my mom, and she’s equally as “filmic” as a soul.