Molly is a pragmatic, highly competent attorney living in Chicago. Originally from Dublin, she has built her life around career achievements and logical planning. She often uses her demanding workload to avoid emotional vulnerability. She dreads the holidays but maintains a decade-long tradition of flying back to Ireland every Christmas alongside her friend Andrew.

Andrew is an Irish expatriate from Cork working as a lifestyle photographer in Chicago. He is warm, deeply connected to his large family, and unapologetically enthusiastic about Christmas traditions. Recently sober, Andrew provides a steady, patient presence that contrasts with Molly's high-stress lifestyle.

Zoe is Molly's identical twin sister who lives in Dublin. She is pregnant with her first child via a sperm donor. Her laid-back, adaptable personality contrasts heavily with Molly's rigid need for control. She often acts as the emotional anchor for her sister.

Hannah is Andrew's youngest sister. She is a spunky and observant teenager with aspirations to become a fashion designer. She shares a remarkably close relationship with Andrew and brings a bright, teasing energy to the family dynamic.

Gabriela is Molly's close friend and coworker at the Chicago law firm. Coming from a family of lawyers, she genuinely thrives under the pressure of their heavy workload. She acts as an emotional sounding board and a practical problem-solver for Molly's chaotic travel plans.

Christian is one of Andrew's younger brothers. He lives in Ireland and helps their father run the family farm, though he occasionally expresses frustration about the manual labor expected of him. He is protective of his brother's happiness.

Oliver is Andrew's gregarious cousin living in London. He house-sits an expensive property for his boss. His heavy drinking and chaotic, party-centric lifestyle create friction with Andrew's commitment to sobriety.

Colleen is Andrew's mother, who oversees the bustling Fitzpatrick household in Cork. She cooks extensive holiday meals and warmly welcomes guests, though she struggles to process sudden changes in her children's lives.

Sean is Andrew's father. He manages the family's cattle farm in rural Ireland alongside his sons, representing the grounded, agricultural roots of the Fitzpatrick family.

Liam is Andrew's oldest brother. He lives on a separate farm nearby with his wife and two children, remaining tightly woven into the extended family's daily life.

Hayley is Molly's college roommate. Self-absorbed and unfaithful, she actively cheats on Andrew, creating the initial awkward situation that forces Molly to intervene during their very first flight together.

Molly's mother lives in Dublin. Unlike the Fitzpatricks, she does not decorate elaborately or make a grand event out of Christmas, which Molly misinterprets as indifference. She quietly but deeply values having her daughters home.

Ava works as a nurse in Ireland. Andrew used to babysit her when she was a child, and she kindly offers to give him and Molly a ride back toward Cork on Christmas Day.

Mark is one of Molly's former boyfriends. During their relationship, he makes a possessive display at the airport, clearly feeling threatened by Molly's ongoing, close friendship with Andrew.