Martha Plimpton is an American actor who made her name as a teenager in films such as The Mosquito Coast and Running on Empty, appearing alongside her childhood sweetheart River Phoenix. Her work on Broadway has ranged from The Coast of Utopia to Top Girls. Most recently, she starred in Sweat at the Donmar Warehouse, a searingly topical play by Lynn Nottage that examines the deep-rooted discontent and anxiety that helped put Donald Trump in the White House. Sweat transfers to the West End next week.

Would you like to see more working-class stories like Sweat on our stages and screens?
Absolutely. One of the things I love about the play is it’s about people whose stories we don’t usually hear or see. What is so compelling is how very human and universal the feelings are that Lynn is writing about. It’s more than just a story of factory workers; it’s about living in a culture of fear and being afraid of losing your place and losing control. My character, Tracey, is afraid not only of being unable to protect her job, she’s afraid of losing something she identifies with so tightly that without it she feels the world is falling apart. These ideas and feelings need exploring because people all over the world, not just in Trump’s America, are going through them.

When Tracey’s livelihood is threatened she turns hateful and racist. How does it feel portraying that side of her?
It’s challenging but it’s not helpful for me to judge her. It has to be very much about just playing the play and, as with a piece of music, you need your low notes and your high notes. And with Tracey, sometimes I have to play some pretty low notes.

Do you prefer stage or screen?
Right now, the more interesting parts are in the theatre, but there’s lots of great stuff in television, too.

What about movies?
Hollywood movies have no appeal for me. I rarely even go to see one – and I’ll tell you why. There are about five women in all Hollywood movies for a period of about three years. Then you get a new crop of five women who are allowed to make movies for the next three years and so it goes on. And the men are allowed to age but not the women. TV is more diverse and interesting and so are independent films. I like films that are made in Britain and in Europe.

You were born into an acting dynasty, the daughter of Keith Carradine and Shelley Plimpton. Was it inevitable you were going to become an actor?
It was probably always going to work out this way. My parents met doing the original production of Hair in New York and I was three by the time my mom left the show, so my earliest days were spent in dressing rooms. Backstage felt like home, just a normal place to be. You could say I’ve spent pretty much my whole life in theatres. I was eight years old when I first went on stage.

How do you look back now on your time as a teenage movie star in films like The Goonies and Running on Empty?
It was a great time to be in movies because there were tomboys in films and those were the parts I used to get. But we don’t see tomboys on screen any more.

Why not?
American cinema doesn’t like women or girls who don’t fit a certain mould and that’s because movies aren’t being written or made by women. But there’s so much great content now on other platforms that Hollywood is quickly becoming irrelevant.

How did you avoid the fate of so many child stars, who often burn out too young on drugs and alcohol?
I grew up in New York and being an actor was more interesting to me, I guess.

As well as an actor, you are an abortion-rights activist and founder of the pressure group A Is For. How do you feel about the recent vote in Alabama to ban abortion?
Obviously, I am enraged. I am furious. I am terrified for the women of my country and the girls. Alabama’s not alone. We know their endgame is ultimately to have Roe v Wade [the 1973 supreme court ruling enshrining in law a woman’s right to terminate a pregnancy] struck down. We need to see the writing on the wall and recognise that Trump is an incredibly dangerous individual. My country is in the throes of something extremely serious and women are paying the price, as they always have.

What made you choose to go public about your own experiences of abortion a couple of years ago?
I want to end the shaming that goes on around abortion and you can’t de-stigmatise something if you’re not willing to talk about it.

I notice you’re not on Twitter, which is unusual for an activist. Why is that?
I quit. It wasn’t the abuse I minded so much as the fact that I didn’t find it useful or productive. These are echo chambers; you are not reaching anybody who needs to be reached and you’re not communicating with anybody in a real way. It also seemed to eat a lot of time.

When you’re not acting or campaigning, what do you like to do?
Wildlife tracking is my new favourite thing. I just took a course in Botswana and it was fantastic. You have to study and do a lot of reading, then you go out in the bush and try to find lions and tigers and all sorts of creatures: birds, millipedes, elephants. You trail them and learn their behaviours, personalities and habits. It’s changed my life.

How so?
It is a bit like meditating or yoga. Some people go on silent retreats and this is my version of that. I think it has helped focus me and made me feel more human.

What else makes you happy?
Gardening. Being in London. I really love it here.

What do you love about it?
It’s pretty. I like the people, I like the diversity and I like the tube, which is very efficient and clean compared to the New York subway. I like pub life, I like Sunday roasts. I like walking by the river and the swans in the parks. I like it when the guy in the shop calls me “love” or “darling”. I like going to the theatre in London. I got to see Maggie Smith in A German Life at the Bridge, which was awesome. The city has got under my skin. The change of scenery is good for me.

Are you planning to relocate here long term?
I have my UK residency now, so who knows? New York isn’t the city I grew up in any more. Even though I love my neighbourhood, my home and my friends, I feel alienated from my country. I know you guys are having similar problems here but I feel more optimistic about the future in the UK. Something tells me that sanity will prevail here. But in the States, I don’t know. I am feeling mournful about my country.

• Sweat is at the Gielgud theatre, London W1, from 7 June to 20 July

This article was edited on 3 June 2019 to remove a factual error about the legality of abortion in some US states