‘Don’t Think Twice’: The affection and anxiety of an improv team

When Jack (Keegan-Michael Key) informs the rest of his improv group that he’s been hired to perform on the nation’s preeminent late-night sketch series, he waits for a cheer that doesn’t come. Instead, he’s greeted by shocked stares, from jealous teammates trying to process how this happened, how it affects them and how much they hate this jerk right now.

It’s up to someone’s girlfriend, new to the tight circle of friends, to break the silence, chirping congratulations as you do when good things happen to someone with whom you don’t share baggage.

It’s this dynamic — the love and occasional resentment within a group of actors pledged to support each other’s every move — that is at the heart of “Don’t Think Twice,” from writer-director-star Mike Birbiglia, following up on his acclaimed, autobiographical “Sleepwalk With Me.” An improviser himself in college and at New York’s Upright Citizens Brigade Theater, Birbiglia puts his experience to work in portraying Miles, founder of the Commune and the one most disturbed by the success of his juniors.

His other teammates include Samantha (Gillian Jacobs), Jack’s girlfriend and the group’s host, and Lindsay (Second City alum Tami Sagher), who’s jobless and lives with her rich parents. Backing them up are deadpan Bill (Chris Gethard) and underconfident Allison (Kate Micucci, seen supporting the scenes of others but never initiating any).

“Don’t Think Twice” is set in the New York improv scene that owes a lot to transplanted actors who taught what they learned in Chicago. Lest this be overlooked, black-and-white footage shows Second City players in the ’50s and ’60s as the movie’s stars spell out the rules of the art form. (Improv vets Sagher and Gethard are credited as consultants, and longtime Chicago teacher Liz Allen had the job of directing the Commune into a true ensemble.)

Jack’s good fortune comes at a rough time for the Commune, about to be booted from their longtime theater and fretting about their future. Just when they’ve settled into this world where misfits fit and the artistic (if not the financial) rewards are many, the doubts start setting in about whether one can improvise forever.

Jack’s jump to bigger things amplifies the worries. “Your 20s are all about hope,” Bill laments. “Your 30s are about how dumb it was to hope.”

Showing a good sense of improvisers’ unique energy, Birbiglia has the Commune people hanging out offstage too, needling one another and reflexively impersonating every voice they encounter. That tic goes to an extreme when one member’s ailing dad musters a couple of words from his hospital bed and the teammates can’t help but goof on it.

Little details bring some of the movie’s biggest laughs: the student unabashed about wanting a TV gig right away, the viewers gawking dumbfounded at some weird musical guest on the late-night show (a note-by-note knockoff of “Saturday Night Live,” complete with booming announcer and haughty boss). Ever dreamed of going to the exclusive, storied “SNL” afterparty? “Don’t Think Twice” offers its own version — twice.

The teammates are presented as generally at ease on stage, selflessly backing up and building on each other’s ideas. But their rapport is more fragile than it should be after 11 years, and when they face an audience distracted by Jack’s new fame as well as a visiting celebrity, they lack the skills to roll with it and the show collapses.

Key, who lived through a lot of this as a Second City performer, a “Mad TV” cast member and a star of the acclaimed “Key & Peele,” convinces both with his TV-friendly charisma and his credible struggle over helping his teammates vs. himself. Having cast himself as an ostensibly pathetic figure, Birbiglia brings us an effective transition of a guy (from Naperville) letting go of his unrealistic dreams and his desperate cling to youth.

It’s a movie that fleshes out the people who entertain us, not with bemusement like a Christopher Guest mockumentary, but with compassion. It’s improv’s version of “Almost Famous” or “Slapshot” or “Tin Cup” or “Jerry Maguire,” ending not with a grand victory but with the small triumph of some people getting to continue doing what they love.

“This American Life” creator Ira Glass, a “Don’t Think Twice” producer, will answer questions after the 2, 4:30, 7 and 9:30 p.m. screenings Saturday, as well as 2 p.m. Sunday.

★★★

The Film Arcade presents a film written and directed by Mike Birbiglia. Running time: 92 minutes. Rated R (for language and some drug use). Opens Friday at the Music Box Theatre.