HOLLYWOOD — Frankie Shaw tugged at her nubby wool sweater as she dashed across the lot of Sunset Gower Studios. It was nearly 80 degrees in Los Angeles in mid-October, but she was dressed for a winter day in Boston — the setting of “SMILF,” Showtime’s new dark-humored series about a young single mother.

Not only does the 35-year-old Ms. Shaw star in “SMILF,” but she also serves as the showrunner, a writer and an occasional director and editor. These responsibilities require extreme multitasking. Grabbing lunch while conducting an interview, Ms. Shaw was handed a note informing her that the next scene was shooting in 20 minutes. But she had to get her hair and makeup done, a 40-minute process. She stared at the note dumbfounded, as if trying to figure out how to circumvent the laws of physics.

After five years of struggle to get “SMILF” made, Ms. Shaw doesn’t mind hustling a little more. Loosely based on her own life, the series follows Bridgette Bird, a working-class, 20-something actress raising a toddler in a cramped South Boston apartment. Bridgette is a ball of confusion and desire, craving sex and food and love and basketball with ravenous intensity — all while trying to pay the bills.

[Review: ‘SMILF’ Tallies the Costs of Motherhood]

A fan of the abrasively realistic depiction of motherhood on “Roseanne,” Ms. Shaw was determined to create a vision of modern parenting that resembled her own ramshackle experience. In the first episode, Bridgette interrogates her gynecologist about the state of her vagina, leaves her toddler alone while she runs to the corner store for junk food and tries to have sex with an ex-boyfriend while her son silently snoozes beside them. The guy flees when he notices a tiny foot stirring under the blankets.