With Lady Bird, Greta Gerwig has come up with what will surely be one of the best films of the year.

Lady Bird, written and directed by Greta Gerwig. Screening at Kendall Square Cinema, Coolidge Corner Theatre, AMC Boston Loews Boston Common.

Saoirse Ronan in a scene from “Lady Bird.”

By Tim Jackson

I first saw Greta Gerwig in Joe Swanberg’s LOL in 2006. That film was followed by Hannah Takes the Stairs in 2007; it was screened at the Independent Film Festival of Boston, at a time in which Swanberg was starting a prolific career as a key “mumblecorps” director. Gerwig was his darling. She popped off the screen, powered by a lively, ingenuous acting style that fit the spontaneity of that film movement. Still, she was new to acting and was considering concentrating on her playwriting.

But the camera loved her, and Gerwig appeared in the Duplass Brothers film Baghead (2008), one of my favorites among the “mumblecorps” products. Noah Baumbach tapped Gerwig’s quirky and improvisational style for his commercial shot at a “mumblecorps” film, Greenberg (2010), which also starred Ben Stiller. Baumbach and Gerwig have been a couple since 2011. Together they wrote, and she starred in, the French New Wave style Francis Ha (2012), and the less successful Mistress America (2015). I was fascinated by her screen charisma and journeyed to New York to see her on stage in Penelope Skinner’s The Village Bike. It wasn’t good. Her wacky shtick was wearing thin. She needed grown-up roles, which she found in Mike Mill’s 20^th Century Women, Todd Solondz’s Wiener-Dog and Pablo Larraín’s Jackie. I looked forward to seeing if she could draw on her maturing energy for her debut as a writer-director.  And she does: with Lady Bird Gerwig has come up with what will surely be one of the best films of the year.

The central idea of Gerwig’s narrative: pay close attention to the people and places that form one’s life. Christine McPherson is 17 and growing up (as did Gerwig) in 2002 in Sacramento. The film begins with a quotation written by another Sacramentan, Joan Didion: “Anybody who talks about California hedonism has never spent a Christmas in Sacramento.” Christine (Saoirse Ronan) is on a quest to find herself and escape that city. (Says Gerwig: “It’s very true of 17 year olds. You don’t realize how beautiful a place is until you step away.”) Christine wants to help create her own future, which means taking on the self-proclaimed appellation of “Lady Bird.” “Is that your real name?” asks her Catholic School drama teacher (August Wilson mainstay Stephen Henderson) at an audition for Merrily We Roll Along at the Catholic School she attends. “Yes.” “Who gave it to you?” he asks. “I gave it to myself. It was given to me by me,” she declares emphatically.

Lady Bird is not a rebel in search of an identity; she is the kind of teenager who both embraces and resists her surroundings. Gerwig’s screenplay, while built on ‘coming-of-age’ tropes, never descends into cliché. Yes, the situations are familiar, but the dialogue reflects thorny reality, examining the paradoxes of human nature in small and subtle ways. Riding in the car, listening to Alanis Morissette’s “Hand In My Pocket,” Lady Bird tells her father (Tracy Letts) “She wrote this in, like 10 minutes.” Her father’s reaction: “It sounds it.” But the lyrics to the song embrace the film’s central idea about contradictory uncertainty of youth:

I’m broke but I’m happy
I’m poor but I’m kind
I’m short but I’m healthy, yeah
I’m high but I’m grounded
I’m sane but I’m overwhelmed
I’m lost but I’m hopeful baby
What it all comes down to
Is that everything’s gonna be fine fine fine

Her father is joking with her, not dismissing her taste in music. Lady Bird knows the difference. Her mother, Marion (Laurie Metcalf), turns out to be a more challenging story. In the opening shot, she and Lady Bird lie asleep, head to head — it is a brief moment of peace. Otherwise, they are in constant conflict. Marion’s hyper-critical, often outright cruel, comments reflect a traumatic past: we get some backstory via a quick sentence that comes at the end of an impassioned sermon about keeping up a clean room. The teen’s father, Larry, while kinder and more supportive, is on anti-depressants and is being pushed out of his job because of his age. He patiently waits out the mother-daughter battles and sibling spats. This dad, despite the daily melodrama, is devoted to both his family and his wife. “Does mom even like me?’, asks Lady Bird. “Well, you’re both strong personalities,” he responds calmly.

Her brother, Miguel, with a face full of piercings, appears to have been adopted. His Goth girlfriend Shelly (Marielle Scott) has been taken in by the family. “My mother hates me,” Lady Bird tells Shelly after a particularly nasty bout with her badgering mother. “She’s got a really big heart,” Shelly says. “She took me in when my own mother freaked out about premarital sex or whatever.” The story is left hanging, but the sentiment registers. Revelations are made through an economy of dialogue and a sharp respect for the ambiguity of human behavior. Everybody seems to be coming of age in Lady Bird’s world; everyone is a work in progress, filled with uncertainty, pain, and doubt. What seems to underline it all is a need to love, forgive, and move on.

As Lady Bird, Saoirse Ronan makes a complete transformation from her Academy Award nominated role as Eilis, the homesick Irish immigrant in 2015’s Brooklyn. In this superb performance, Ronan — her complexion mottled and her hair ragged and dyed red — seems to be channeling the persona Gerwig cultivated in her own early roles. Lady Bird is comically forthright, undaunted by limitations of wealth or circumstance. She learns from life’s contradictions. The usual adolescent travails — high school crushes, friendships, burgeoning sexuality, and Catholicism — are not obstacles, but opportunities that help her shape who she will become. Ronan’s face registers everything — thoughts and emotions.

The rest of the cast are a gift to a first-time director. Metcalf gives a beautifully complex performance. Actor and playwright Letts proffers a nuanced performance as Lady Bird’s quiet and patient father. Nobody  hides pain under a unruffled exterior better than he does. Timothée Chalamet (Call Me by Your Name) plays the hunky, bookish, conspiracy spouting indie rock boyfriend. Lucas Hedges (Manchester by the Sea) is the musical theater boyfriend with sexual identity issues, while Beanie Feldstein (Jonah Hill’s younger sister) is delightful as Julie. She is a “plus size” girl, but that condition is never referred to and is not used as a plot device. Instead, Julie is kind, vulnerable, smart, a terrific singer and Lady Bird’s confidant.

Finally, there is the incomparable Lois Smith (Marjorie Prime), who illuminates the small role of Sister Sarah Joan. The 87-year-old actress’ film career began with James Dean in 1953’s East of Eden. Over the decades she has appeared in countless films and stage productions; her turn in a 2015 stage production of dramatist Annie Baker’s John was remarkable. Here, every glance, gesture, and flutter of her voice is perfection. It epitomizes the marvelous achievement of Lady Bird.

Tim Jackson was an assistant professor of Digital Film and Video for 20 years. His music career in Boston began in the 1970s and includes some 20 groups, recordings, national and international tours, and contributions to film soundtracks. He studied theater and English as an undergraduate, and has also worked helter skelter as an actor and member of SAG and AFTRA since the 1980s. He has directed three feature documentaries: Chaos and Order: Making American Theater about the American Repertory Theater; Radical Jesters, which profiles the practices of 11 interventionist artists and agit-prop performance groups; When Things Go Wrong: The Robin Lane Story, and the short film The American Gurner. He is a member of the Boston Society of Film Critics. You can read more of his work on his blog.