Gillian Jacobs can’t remember the last time she went on holiday. She keeps being told that she needs to take some time off, but she’s far too busy to press pause. Not even lockdown could slow her down. “A lot of people have said I need to get more hobbies,” she laughs infectiously. “That’s something I struggle with: what do I do outside work? I try to find more work for myself, that’s what I usually do.” She erupts in another fit of giggles.

The 37-year-old actor’s work ethic has paid off handsomely. She seems to have carved out her own niche playing complicated, messy women, who are usually struggling to get their lives together. There was self-righteous activist Britta Perry in the experimental TV comedy Community, the pretentious artist Mimi-Rose Howard in HBO’s Girls, and the self-destructive addict Mickey Dobbs in Netflix’s Love. Jacobs isn’t afraid to play people who are hard to like and yet always manages to root out something sympathetic among the hard knots of her characters.

Why is she so drawn to playing free-spirited rule breakers? “Even though I might not externally resemble all the characters I’ve played, I think the internal struggle is very relatable of what these various women are going through,” she says.

Her latest role is in director Kris Rey’s low-key comedy I Used to Go Here, produced by Saturday Night Live’s The Lonely Island. She stars as Kate, a thirtysomething writer getting over a broken engagement as her first novel is released to dismal reviews. Her life is at a crossroads when her old college professor David (Flight of the Conchords’ Jemaine Clement, brilliantly sleazy) invites her to give a reading at her alma mater. She accepts, hoping for a much-needed ego boost and quickly finds herself entangled in the lives of the students she meets.

“As an actress, you’re always looking for a complex, flawed, real character,” says Jacobs. “Sadly, there isn’t an overabundance of those so it felt like a real opportunity when I read this script.”

Jacobs is so warm and engaging over the phone from her home in Los Angeles, always quick to laugh while tackling each question with sunny enthusiasm, that it’s almost hard to believe she is “not the most socially adept”, as she confesses to being. Acting was her escape from a lonely childhood as an only child with no friends. Her mother, who brought her up on her own in Pittsburgh, Pennsylvania, decided to enrol her for acting classes when she was eight after Jacobs’ school called to say she had been talking to herself on the playground.

The moment Jacobs started acting, she was smitten. That’s until she ended up in drama school. While attending Juilliard, the prestigious New York performing arts conservatory, she became consumed by self-doubt and started questioning whether she was cut out to be an actor after being frequently criticised by her teachers. But she stuck at it. “I felt I wasn’t qualified to do anything else,” she admits.

She credits therapy for guiding her through the fug of confusion and helping her to rediscover her love for acting. Parts followed in the gritty film drama Blackbird and the TV show Law & Order: Criminal Intent, but since her breakthrough role in 2009’s Community, she has steadily gravitated towards comedy. Films such as Netflix’s enjoyable romcom Ibiza and sweet indie gem Life Partners have showcased Jacobs’ impeccable comic timing.

Many of her best-known characters have an edge of snarky cynicism. Is she a cynical person? “I don’t know if at my core I am but maybe that’s my little outer shell.” She shares a story from high school. Everyone had to decorate a shirt with nicknames and jokes. “But I didn’t really have enough friends to have a nickname so I just put ‘cynic’ on the back. A boy in my homeroom said: ‘Si-nike, what’s that?’ I was like: ‘It’s cynic,’” she growls in mock anger.

In I Used to Go Here, Kate finds comfort in regressing to her college days as she starts hanging out with the new students who live in her old house. The past still holds the promise of great things while, in the present, she’s choking on the ashes of those once-cherished dreams. It’s a gently humorous coming of age tale for those in their mid-30s still grappling with adulthood, anchored by a subtle and touching performance from Jacobs.

Her own college days were much more sedate than Kate’s raucous second shot at student life. “It was very strict and rigorous. I had a college experience of being in class all day and then being in rehearsal every night.” How did she relax? “Going to a bookstore and looking at magazines,” she sighs with satisfaction.

Jacobs has been teetotal her whole life after “watching people in my family grapple with addiction”. She has never drunk alcohol, smoked or taken drugs. “As a kid, I made the decision to never drink,” she says. “Then, because I’m stubborn, as I got through high school and college, the more people tried to get me to drink, the more firm I became in my resolution.”

During lockdown, the actor reunited with her former Community castmates, including Donald Glover and Alison Brie, for a virtual table read to raise money for Covid-19 relief efforts. Since then, there has been much speculation about whether there will be a film adaptation of the much-loved show that ended in 2015. “I think everyone would like to do it,” Jacobs says. “I love hanging out with them.”

Another role she would like to return to is that of Mickey Dobbs. While Love was cancelled after three seasons, Jacobs feels there is still mileage in the romance between Mickey and Gus (Paul Rust), even though the last series tied things up neatly. “More shows these days have a time jump between the seasons,” she says. “It would be fun to see where they are. Are they still married?”

Acting may have opened up new paths for Jacobs but there is one thing in her life that remains the same. “My own conception of myself is as a loner,” she says, an indication perhaps of why directors such as Love creator Judd Apatow keep on casting her in quirky misfit roles and why she brings such soulful depth to these characters. “I wonder if that’s my default setting,” she muses, before adding gleefully: “Thankfully, I do have friends now!”

• I Used to Go Here is out now on digital platforms.