Melissa McCarthy takes a dramatic turn in ‘Can You Ever Forgive Me?’

Melissa McCarthy in a scene from “Can You Ever Forgive Me?”Twentieth Century Fox

In addition to its other strengths — serving as a reminder of the kind of small, satisfying movie they don’t make anymore, showcasing the depths of Melissa McCarthy’s talents — “Can You Ever Forgive Me?” celebrates a hardy but endangered species: the Nasty New Yorker. It’s been a while since I’ve enjoyed spending so much time with someone so unpleasant.

The movie’s not one of McCarthy’s big, splattery farces but rather a beautifully nuanced drama of human comedy, based on a true story. Lee Israel (McCarthy) was a Manhattan writer of celebrity biographies with a few successes in her past and a lot of burned bridges in her present. In 1991, she stumbled upon a novel means of paying the rent: Forging letters from famous dead people and selling them on the memorabilia market.

She was eventually caught, of course, and ended up writing a book about her experiences, which shares the film’s title but isn’t credited as a source. Instead, director Marielle Heller and screenwriters Jeff Whitty and Nicole Holofcener (herself a notable writer-director) create a marvelous character portrait of a most dyspeptic woman.

McCarthy’s Lee Israel is a specific New York type: the literate crank. She lives alone in a rent-stabilized Upper East Side apartment with only a cat for company — Lee had a girlfriend once but long ago chased her away — and she rages at a world that has little time for the cultural past. “No one wants to read a biography of Fanny Brice,” her exasperated agent (Jane Curtin) barks, and even if that’s not entirely true — I’d read a biography of Fanny Brice — Lee’s rough edges, drinking habit, and disdain for personal grooming have pushed her to the fringes.

In her researches, she comes across an undiscovered Brice letter and, in a moment of whimsy, types a comic P.S. at the bottom. It sells. So does the Brice letter she invents from whole cloth, as do the letters she composes ondying typewriters from dead authors: Noel Coward, Edna Ferber, Lee’s beloved Dorothy Parker. She’s no longer a biographer but has, in a real sense, become her subjects. Even she recognizes it’s some of her best writing.

In all this, Lee is abetted amorally, alcoholically, and, in time, criminally, by John Hock, an aging gay hustler played with gusto by that great British ham Richard E. Grant (“Withnail and I”). “Can You Ever Forgive Me?” is a joy if for no other reason than to watch these two social outcasts express their contempt for the rest of civilization in bon mots grandiose (his) and grumpy (hers), occasionally musing over a book editor who either died or moved to the suburbs — it’s all the same.

Heller’s first movie, “The Diary of a Teenage Girl” (2015) was the kind of clear-eyed chronicle that managed to like all its characters while never letting them off the hook, and she repeats the trick here, creating in Lee Israel a woman who might be unbearable in life but whose movie incarnation is sad, funny, moving, and somehow cheering in her cockroach will to survive.

This is McCarthy’s finest performance yet and, honestly, one of the best of the year. Lee has no fashion sense, a battle-helmet hairdo, and she despises everyone except her cat — and the star digs right in and finds the pride warring with the insecurity, the tenacity with which a talented, unseen woman does daily battle with the world. McCarthy uses her fluid facial expressions masterfully; in a scene with a lonely bookstore owner (Dolly Wells) who might become more than a friend, we watch Lee’s heart open up and warily close down in discrete increments of self-preservation.

Finally, “Can You Forgive Me?” is a sweet and scruffy document of a Manhattan that probably no longer exists — when a writer could live on fumes in a walk-up apartment in a city that still had bookstores and people who cared about them. Where you came from Brooklyn rather than going there, and where listening to classic vocalists (Lee’s picks: Jeri Southern and Billie Holiday) were what got you through the week and not a cliché from a Woody Allen movie. Where the past was valued rather than the knock-down present and the high-rise future.

This movie remembers that New York with love — and a little larceny.

***½

CAN YOU EVER FORGIVE ME?

Directed by Marielle Heller. Written by Nicole Holofcener and Jeff Whitty. Starring Melissa McCarthy, Richard E. Grant. At Boston Common, Kendall Square, Coolidge Corner, West Newton. 106 minutes. R (language, including sexual references, brief drug use).