Early in Elizabeth Strout’s new novel, My Name Is Lucy Barton, the narrator, a doctor, after wishing his patient good night and leaving her hospital bedside, “made a fist and kissed it, then held it in the air as he unswished the curtain and left the room”. In both its deficiency (an expression of tenderness curbed by protocols both professional and personal) and its sincerity (the militant earnestness of the salute), the gesture seems to contain everything Strout is saying about love: that it’s hard and awkward and will always be inadequately expressed, but that it’s also something we need to grab and hold in our fists. Lucy is recovering in hospital after a mysterious infection following the removal of her appendix. These nine weeks of her recovery become a lifetime – figuratively in terms of her boredom and loneliness, and structurally, as Lucy tells the story of her childhood, marriage and, most important of all, how she became a writer. They’re all meditations prompted by the arrival of her estranged mother, whose expressions of love are even more compromised than the doctor’s raised fist.

There are pieces of me in every character, because that’s my starting point, I’m the only person I know

Writing in the New York Times, the novelist Claire Messud proclaimed Lucy Barton an “exquisite novel”, praising its “careful words and vibrating silences”. Hilary Mantel marvelled at “an attention to reality so exact that it goes beyond a skill and becomes a virtue”. Since its publication in the US last month the book has been riding at the top of the New York Times bestseller list.

Strout, who turned 60 last month, lives in a homely and book strewn apartment in a grand building on the Upper West Side of Manhattan. She is seated at a pine dining table so crowded with flowers that I worry someone has died. But no. “These are from my English publisher,” she says, “and these are from a dinner last night!” And she laughs, embarrassed at this minor theft. That kissed fist gesture the doctor makes was, she says, stolen, too: “I don’t know where I saw that, but I do think I saw it.”

The HBO adaptation of Olive Kitteridge

Her five novels have begun “always, always” with a person, and her eyes and ears are forever open to these small but striking human moments, squirrelling them away for future use. “Character, I’m just interested in character,” she says. But readers, more than ever, are also interested in the author. In 2008 Strout published Olive Kitteridge, a collection of 13 short stories set in the small fictional town of Crosby, Maine, in which the lives of its residents, in all their public disappointments and private desires, thread through the life of Olive, a retired schoolteacher who’s as unwitting in her tyranny as she is in her kindness. When US radio host Terry Gross recently mentioned the suicides that run through the Pulitzer prize-winning novel, Strout conceded: “There is a history of suicide in my family, and I think that it’s always been very compelling to me as a result,” but declined to elaborate. Strout has made herself vulnerable to further autobiographical readings with the character of Lucy Barton, a writer who grew up in an isolated and strict family in a small rural town in Illinois (Strout grew up in small towns in Maine and New Hampshire), and now lives in New York, having found writing success later in her life.

Yet Lucy’s mentor, an older writer named Sarah Payne, at one point tells an audience sharply that it is not her job “to make readers know what’s a narrative voice and not the private view of the author”. The rebuke seems to blast out directly through the book’s fourth wall.

“You know, there’s always autobiography in all fiction,” Strout says. “There are pieces of me in every single character, whether it’s a man or a woman, because that’s my starting point, I’m the only person I know. But yes, Sarah Payne ... I realised in that scene, ‘OK, here’s a chance to let people know.’” She goes on to explain: “You can’t write fiction and be careful. You just can’t. I’ve seen it with my students over the years, and I think actually the biggest challenge a writer has is to not be careful. So many times students would say, ‘Well, I can’t write that, my boyfriend would break up with me.’ And I’d think ...” she sucks her teeth, “‘Well, OK, I’m sorry, I don’t really have much more to tell you.’ You have to do something that’s going to say something, and if you’re careful it’s just not going to work.” Or, as Sarah Payne tells Lucy, “We all love imperfectly. But if you find yourself protecting anyone as you write this piece, remember this: You’re not doing it right.”

Strout spent years toiling as a writer without getting anything published. “I sent out stories and I didn’t even get, ‘Try us again,’ I just got,” she makes a shooing away gesture, “the basic ‘No.’” She remembers hearing the writer and critic Francine du Plessix Gray say it takes 10 years of solid writing to get good at a time when Strout had already put in a good 15. “I was very slow at getting up to that ability to have the sentences do what I needed them to do. I probably was too careful for a long time.”

By the time she wrote her first novel, 1998’s Amy and Isabelle, “I could just handle a sentence better because I’d been writing for so long, I could get the sentence to go into that crevice.” More importantly, she was riding on a liberating, nothing-to-lose bravado: “I thought, ‘Probably no one will ever read this – oh well, just write it.’”

The novel, which details the fraught relationship between an isolated mother and daughter, was nominated for several awards and made into a TV movie in 2001. Four more books have followed and that “Oh well, just write it” sentiment has remained.

“With Lucy the first huge surprise was that I made her a writer. I just couldn’t believe it – I thought, ‘You’re doing first person, and then you’re going to make her a writer?’ That felt almost boring because who wants to read about a writer? But it was that little scrap where she’s in the schoolroom and she’s reading and she realises books are broader things and made her feel less alone. And then I realised, ‘Lucy, you’re going to have to be a writer.’”

Like Lucy, Strout read a book when she was very young about a girl “who was strange and unattractive because she was dirty and poor”, and Strout felt less alone. Like Lucy, it made her want to be a writer. “I realised,” Strout says, “I will never see the world except through my own eyes, and that was a remarkable thing to realise. I think many people live their whole lives and don’t realise that.”

Books were about the only miracles Strout had growing up. At one stage, her family lived on a dirt road, and such was her parents’ strictness that there was no TV or newspapers, just the New Yorker. Her father was a professor and her mother a teacher; they believed in education, but not in the outside world. As she once put it, they had, “a skeptical view of pleasure”. When she went to college she had only seen two films: 101 Dalmatians and The Miracle Worker. Her mother did, however, give her notebooks and encouraged her to write; to this day her mother reads every new book within a few hours of receiving it and then calls her daughter to tell her it’s her best yet.

Frances McDormand as Olive Kitteridge Photograph: Allstar/HBO

After graduating from Bates, a liberal arts college in Maine, Strout dragged herself off to law school in 1981 because she had a “social conscience and I wanted to do good things, and I thought, ‘Law is language ...” she makes a face. “I was just so misinformed. I came out and I was just an awful, awful lawyer for six months, and that’s when I had the realisation, ‘If I’m 58,’ which seemed ancient, ‘and I’m a cocktail waitress, and I haven’t published anything, that will be pathetic.’ I remember thinking, ‘If I’m dying, at least I can say to myself I tried, I really tried for it.’ I thought, ‘Let’s just go for it.’”

And five years before she turned 58 she won the Pulitzer prize. “I’m glad I was older when I got it – because I think it might have knocked me off my feet when I was younger. It’s funny because I know it was good and I know it brought me a lot more readers, but it doesn’t feel particularly real.” She felt a similar way about the Emmy award-winning HBO TV version that followed, with Frances McDormand as Olive Kitteridge.

“I just loved it. But it didn’t feel like it had much to do with me. Every so often I would recognise – Oh, I made that man, I wrote that! – I know what happens next!”

Olive – recalcitrant, blunt and an often impossible wife and mother – is an indelible creation, offering an implicit “hell’s bells” (her favoured expletive) to the fallacy that female characters should be “likable”. She is something much more compelling than likable, she’s real. Strout recounts her astonishment at meeting a group of young women in Connecticut, “affluent, all skinny little things”, who held weekly “Olive meetings” at Starbucks. “I was thrilled! I thought, ‘That’s fabulous that Olive speaks to them.’ I think there must be a lot of things that people don’t say that Olive says for them.”

The story in which she steals her new daughter-in-law’s bra and shoe and subtly defaces one of her sweaters, for example, still impels confessions from readers. “People – women – will say to me, ‘How did you know?’ And the conspiratorial look they give me makes me realise if they haven’t done that, they want to.”

It’s fabulous that Olive speaks to women. I think there must be a lot of things people don’t say that she says for them

So much of the power of Olive Kitteridge – and of My Name Is Lucy Barton – comes from Strout’s resistance to sentimentality. It is, she thinks, “a cheap route to something and that’s not what I want to do. I don’t want to write melodrama; I’m not interested in good and bad, I’m interested in all those little ripples that we all live with. And I think that if one gets a truthful emotion down, or a truthful something down, it is timeless.”

Strout still thinks of herself as having “excessive emotion”: “Ageing doesn’t seem to have taken care of any of those problems. I still feel like I’m dripping with emotion. But the work distils it. It’s good for me.” And yet: “There are times when I have thought, ‘What have I done? I’ve just written some books.’ There’s so much awful stuff out there and maybe I should have been doing something more actively. But ever since I was young, I have seen writing as trying to help people. That sounds so corny but that’s really what I see as my job – trying to open somebody’s eyes just a little bit for one minute. So, yeah, there are times I think, ‘This is foolish,’ but I don’t know that it’s any more foolish than any other acts of trying to help the world.”

• My Name Is Lucy Barton is published Viking (£12.99). To order a copy for £10.39 go to bookshop.theguardian.com or call 0330 333 6846. Free UK p&p over £10, online orders only. Phone orders min p&p of £1.99.