Laurie Metcalf, left, and Saoirse Ronan in Lady Bird (TIFF)

Actress-turned-filmmaker Greta Gerwig’s solo directorial debut stood apart from most of the selections at the Toronto International Film Festival, which in a sampling of more than three dozen films, skewed heavily toward the European art house. At a tight 94-minute running time, writer/director Gerwig makes every scene count, and the film rolls along, never stopping. Lively, rambunctious, and thoughtful, it was refreshing viewing after so many unemotive, austere, and slowly-paced dramas.

What helps the movie jump to the head of the class of teen comedies is the movie’s setting, which is Sacramento, California, in 2002, and the specificity of the lead character. Gerwig takes tropes and themes from so many YA novels and teen movies and then smashes them together: first love, the first time, infiltrating the popular crowd, a sad/happy prom night, etc. Many of the scenes are stand-alone vignettes, making this the type of movie that offers repeated viewing and is easy to dive into and hard to pull away from. It’s not unlike Clueless, back in the day when it seemed like it was always on HBO.

Story-wise, this is nothing you haven’t seen before, which combined with the grainy, low-contrast cinematography and old-school Academy ratio, gives it a no-frills, it-is-what-it-is approach. It’s how Gerwig puts her characters through their paces that counts. The free-spirited story line offers the simple pleasures of a knowing film about a pretentious and not fully perceptive protagonist, a target ripe for pie-in-the-face moments.

Christine McPherson (Saoirse Ronan), a senior and the new kid at a Catholic high school, insists on being called by a name she chose for herself, Lady Bird, though her tough-minded and often tactless mom, Marion (Laurie Metcalf), hasn’t gotten the memo. One moment mother and daughter are crying together, listening to the audiobook conclusion of The Grapes of Wrath, and in the next the mother is asking the heavens, “How did I raise such a snob?” (Even when offering a half-hearted compliment, Marion’s dour expression says it’s anything but.)

Christine lives moment to moment, and like many a teen heroine before her, has little awareness of her own self-absorption. She’s confident and knows she’s smart, though her grades don’t always reflect that. In this school setting, brains don’t account for much on the social ladder. She’s more of a wallflower, albeit with a barbed wit. Gerwig has supplied Christine some choice one-liners, all sounding credible from a teen mouthing off.

Dad (Tracy Letts, playing the good cop among the parents) is out of work, and mom works double shifts as a nurse, which she makes sure no one forgets. For college, the folks can barely afford in-state tuition, but Christine has a more ambitious and financially formidable objective: she has secretly applied to elite East Coast schools, in order to flee as far from Sacramento as possible. That tension—the lack of money and Marion’s negative assessment (“You’re not going to get into those schools anyway”)—forms one of the connective plot lines. To make her applications shine, Christine tries out with her best friend, Jules (Beanie Feldstein, a find), for the school’s production of Stephen Sondheim’s Broadway flop Merrily We Roll Along—not the typical choice for a high school musical.

However, she’s at her most dramatic in her grand tragedienne moments off-stage. Ever serious, she looks at a Playgirl magazine as if she’s reading a scientific study; she bought that and cigarettes on her 18th birthday for no other reason than she could legally do so.

Metcalf is having a moment this year, having won a Tony Award for The Doll House, Part 2 and returning to the television reboot of the blue-collar sitcom Roseanne. The easily frazzled Marion is a lot like her TV counterpart, Jackie: no-nonsense, stubborn, and nearly always wearing a permanent put-upon pout. Her behavior, though, too neatly fits her daughter’s diagnosis of mom’s personality: textbook passive-aggressive.

Yet Gerwig gives her cast a chance to break out of their archetypes. In maybe the most touching scene, Lady Bird’s one-time boyfriend (Lucas Hedges) has a moving moment of vulnerability, and Marion is also given a private moment that does wonders to soften her prickliness.

In snark and sensibility, the movie is kin with the current explosion of sharply written YA/early adult books, such as I Hate Everyone but You: A Novel by Gaby Dunn and Allison Raskin and Andrea Portes’s Liberty: The Spy Who (Kind of) Liked Me. It is certainly one of the most sharply-written American coming-of-age films in a long while. This movie has moxie.