Most good television comedies take a while to hit their stride. The first two seasons of “Seinfeld” are funny, but it wasn’t until season three that the cast found its snarky rhythm that made the show famous. “Cheers” was the same way; It took a while to develop the right womanizing tone for Sam Malone, and the right stuffy warmth for Frasier Crane. “Girls” has finally settled in, and the show and its cast have grown into something remarkable.

Season three’s narrative picks up a few weeks after the end of season two. Hannah (Lena Dunham), with the help of her on-again boyfriend Adam (Adam Driver), has stabilized her obsessive compulsive disorder and is back to work on her e-book. Marnie (Allison Williams) is continuing the downward spiral she began last year after losing her once-devoted tech developer boyfriend Charlie (Christopher Abbott). Jessa (Jemima Kirke) is in the midst of a six-week stint in a rehab facility, and Shoshanna (Zosia Mamet) is filling her last semester at NYU with one-night stands, chain smoking and binge drinking.  

The principal actors never fail to deliver in full character each time they’re on screen. In previous years, the protagonists were more caricatures than characters: Hannah was an avatar of selfishness, Marnie was all-consumingly ambitious, Jessa obnoxiously flighty and Shoshanna hopelessly naive. They were all easy to predict in every situation. This time around, the characters have been genuinely affected by each other’s presence. Hannah shows a new ambition in her quest for publication, while Marnie masks her slide into depression with a bluster typical of Jessa. Shoshanna still talks incessantly, but now she’s trying on a bit of her friends’ cynicism. 

The difference in character development in season three is astounding. Dunham’s performance has never been stronger. Hannah’s newfound determination feels natural and is balanced by a real emotional vulnerability as she realizes that her desire for greatness has a cost. Her work in two later episodes is Emmy-worthy, as she copes with her complete lack of emotion following a devastating epiphany about the career and life she’s chosen. Dunham has been praised by many in the past for her fearlessness in regards to on-screen nudity, but the real bravery this season is displayed on her face. Her emotional honesty is crushing. As a writer, she never creates easy resolutions for her character; as a director, she doesn’t allow us to look away; as an actor, she makes us feel every blow. 

Her co-stars have done just as good a job of fully realizing the emotions and physicalities of their characters this season. Williams has become adept at knowing exactly when and how to let her character’s cracks show, playing Marnie as a wall of faux confidence. Kirke plays Jessa as guarded and infuriatingly mysterious as ever but slowly allows more hints of darkness and real emotion to creep in than in previous seasons. It seems that she is building up to something, and she gives the audience hints that make putting up with her worth it. Mamet is still charming and offbeat, while leaning into the stresses Shoshanna faces as she moves toward graduation.

Driver continues his remarkable work from the past two years. Adam is bizarre, almost feral at times and beyond idiosyncratic, but he somehow remains the most stable character in the show. Shoshanna describes him as “so dementedly helpful,” and she’s completely right. Any time “Girls” is bogged down, Driver resuscitates it with a mix of madcap energy and true tenderness. Dunham gives him many of the show’s best monologues, and he always runs with the opportunity. 

The third season of “Girls” is, in short, tremendous. Dunham, the show’s creator, writer and show runner, has always focused on subverting viewers’ expectations of what sitcoms can do but by delivering a set of episodes that are poignant, laugh-till-it-hurts funny and, most of all, true. Dunham has finally delivered the show she’s been striving toward.