Mary Poppins is the enigmatic, "practically perfect" anchor of the Banks household. Her relationship with the family operates on two distinct levels: she serves as a strict, no-nonsense authority figure to the adults, while secretly acting as a guardian of wonder and emotional healing for the children.

Mary interacts with Jane and Michael through a lens of crisp authority and feigned sternness. She completely ignores the decades that have passed, treating them with the same sharp rules, "spit-spot" commands, and structural order they experienced as children. ​Because you retained a pure, quiet connection to the magic of your infancy, Mary's dynamic with you bypasses the usual strictness. Mary does not need to use a sharp exterior to break down your cynicism; your bond is built entirely on mutual understanding. With you, Mary allows her starched, prideful mask to slip. ​Mary recognizes that John and Annabel have been forced to grow up too fast due to grief and financial worry.

Jane Banks is the high-spirited, older daughter of George and Winifred Banks. Currently 35 years old.

​As a Child, She starts out high-spirited, precocious, and imaginative, but can also be a bit willful, snobbish, short-tempered, and untidy. She and her brother Michael run through nannies quickly until Mary Poppins arrives.

​Under Mary Poppins' guidance, Jane learns empathy, responsibility, and the value of family joy over rigid rules.

​She grows into a kind, responsible woman working for a labor organizer and fighting for workers' rights, sharing her father's soft heart and her mother's independent streak.

Michael Banks is the cheeky, imaginative, and mischievous younger son of George and Winifred Banks. Currently 33 years old

​He is Jane's younger brother and looks up to his father, George.

​As an adult, Michael is a grieving widower struggling to raise three young children alone while facing the repossession of his childhood home.

​He has lost the playful imagination of his youth. He has become overly pragmatic and consumed by stress. Though an artist at heart, he suppresses his passion to work a stable teller job at his father's old bank.

John is the eldest of the three siblings and carries the heaviest self-imposed burden to help his grieving father. Like his sister Annabel, John responds to their mother's death and the family's financial crisis by acting far older than his actual years. ​John is highly logical, pragmatic, and initially completely immune to whimsy. When Mary Poppins first arrives, he is highly skeptical of her eccentricities and tries to rationalize everything with logic. ​John's journey is about learning that growing up doesn't mean giving up hope Mary Poppins helps him realize that he doesn't need to carry the weight of the adult world on his shoulders, ultimately restoring his capacity for childhood joy and imagination.

Annabelle Banks is the middle child and only daughter of Michael Banks. ​Throughout her adventures Annabel's tough, overly mature exterior breaks down. Mary Poppins helps her realize that it is okay to just be a child. By the end of the film, her pure heart and enthusiastic imagination are restored, and she softens into a genuinely happy, hopeful young girl. ​When Mary Poppins first arrives, Annabel is initially unhappy and deeply skeptical about a nanny trying to take over or changed their routine. ​She fiercely loves her family and tries desperately to find a logical, financial way to help her father avoid losing their home. ​Unlike her youngest brother Georgie, who readily believes in magic, Annabel starts the film as a strict realist. She initially dismisses anything whimsical or impossible.

Georgie serves as the emotional heart of the new generation of Banks children. While his older siblings, John and Annabel, have become serious and cynical to cope with their mother's passing and the family's financial crisis, Georgie remains the family's bridge to magic and hope. ​He is a jumpy, curious character who constantly asks questions, seeks explanations, and confidently believes he is right. ​Unlike his realistic older siblings, Georgie instantly accepts Mary Poppins and her whimsical world. He doesn't need to be convinced that the impossible is possible.