Lenny is a 28-year-old babysitter living in New York City who is completely consumed by grief following the death of her best friend, Lou. Usually vibrant and engaging with children, Lenny currently struggles with basic self-care and avoids her shared Brooklyn apartment, opting instead to sleep on the Staten Island ferry. She carries a laminated "Live Again" list to force herself into new experiences, attempting to pull herself out of her depressive state.

Miles is a former bricklayer from upstate New York who relocated to the city to care for his dying, estranged father. Heavily experienced with profound loss after the sudden deaths of his mother and cousin a decade earlier, he acts as an expert who coaches Lenny through her struggles. Though gruff and socially awkward, he is deeply devoted to building a relationship with his newly discovered half-sister and niece.

Lou is Lenny's vibrant, outgoing best friend who recently passed away following a prolonged battle with cancer. Before her death, she studied art and design at the Pratt Institute and shared a Brooklyn apartment with Lenny. Her enduring spirit and the "Live Again" list she carried serve as the driving forces behind Lenny's journey toward healing.

Reese is a successful and polished single mother living in her late father's apartment. Beneath her intimidatingly perfect exterior, she struggles with the recent death of her father and the shocking revelation of her half-brother's existence. She tends to push people away when overwhelmed and maintains a tense, guarded dynamic with Miles.

Ainsley is Reese's rambunctious and imaginative seven-year-old daughter. Dealing with the absence of her grandfather and her mother's demanding work schedule, she feels lonely but finds immediate comfort and fun in Lenny's care. She is initially confused by her new uncle Miles but slowly warms up to his attempts to connect.

Carp was a famous bluegrass musician who passed away a year before the novel begins. Publicly known as a dedicated family man, he had an affair that resulted in a son, Miles, whom he kept hidden for decades. His death and the revelation of his secret life trigger significant familial conflict.

Eva is Lenny's mother, living in Brooklyn. She considered Lou to be like a second daughter and is grieving that loss while simultaneously struggling with Lenny's sudden distance and isolation.

Kevin is Lenny's father. Like his wife, he is navigating the grief of losing Lou while trying to respect Lenny's boundaries, though he jumps at the chance to welcome her and Miles back into their lives.

Jericho is a cyclist whose mother owns a local bakery. After Lenny stands up for him during a traffic altercation, he becomes a fast friend, eventually attending a K-pop concert with her and integrating into her new support network.

Rica is a friend of Jericho's who quickly folds Lenny into their social group. Supportive and perceptive, she invites Lenny to yoga classes and helps her brainstorm activities to shake up her routine.

Jeffy is part of Jericho and Rica's friend group. He joins the gang for their camping trip and playfully helps nudge Lenny and Miles together during social outings.

Kira is Miles's ex-girlfriend and the former "town sweetheart" of his upstate hometown. She dated Miles for five years following his family tragedy but eventually cheated on him, complicating his standing in their small community.

Anders was Miles's younger cousin who moved in with him and his mother. Miles acted as an older brother to him until Anders tragically died in a car crash alongside Miles's mother, a loss Miles still heavily processes.

Miles's late mother raised him as a single parent in upstate New York after an affair with Carp Hollis. She ensured Miles felt loved despite his father's absence, before dying in a tragic car accident ten years ago.

Harper is Reese's friend who occasionally helps out with Ainsley, stepping in for overnight babysitting duties when Reese is traveling for work.

Marzia is a nosy family friend of the Bellamys who aggressively inserts herself into others' business, loudly broadcasting intimate details of Lou's illness until Miles steps in to defend Lenny.

George is an elderly man grieving the recent loss of his wife. He strikes up a conversation with Lenny at the museum, sharing mutual feelings of profound loss.

Ethan is a friend of Miles from his hometown who owns a bar. He visits the city and discusses business and parenting, highlighting parts of Miles's past life.

Cody is an old friend of Miles from upstate New York and the older brother of Miles's ex-girlfriend, Kira. His wedding brings Miles and Lenny out of the city.

Sean is a man from Miles's hometown. He is currently dating Kira and is the person she cheated on Miles with years prior.

Miriam is Ethan's young daughter, discussed while Ethan and Miles catch up on their lives.