Joss is a highly successful, renowned Black British jazz trumpeter who recently died at age 70. Though assigned female at birth and born Josephine Moore, Joss lived his adult life publicly and privately as a man, keeping his physical reality a secret from the general public, his bandmates, and his adopted son. He views his music as a force that transcends personal identity, using his trumpet playing to express the deepest aspects of his history and humanity.

Millie is a Scottish woman from Glasgow and the fiercely devoted widow of Joss. She kept his assigned gender a complete secret throughout their decades-long marriage, actively binding his chest each morning out of deep love and respect. Following his death, she faces intense media scrutiny, retreats to their secret cottage in Torr, and suffers an agonizing estrangement from her adopted son.

Colman is the biracial adopted son of Joss and Millie, working as a motorbike courier in his thirties. He struggles with a profound sense of failure and lacks clear direction in his life. The sudden revelation of his father's assigned gender by a funeral director leaves him feeling fundamentally betrayed and angry, making him vulnerable to the financial promises of tabloid journalism.

Sophie is a freelance tabloid reporter determined to capitalize on the scandal surrounding Joss's death. She aggressively pursues Colman, aiming to ghostwrite a sensationalized, highly profitable book about his father to secure her own wealth and status. She uses expensive shopping sprees at upscale stores to mask her deep-seated insecurities and chronic depression.

Edith is Joss's elderly, white Scottish mother who remains unaware of her child's passing at the story's outset. She knows Joss only as Josephine and has happily received weekly financial support from him for years without fully understanding his adult life. She lives quietly, avoiding wastefulness, and frequently reminisces about her late husband.

John is Joss's late father, a Black immigrant from the West Indies who arrived in England at the turn of the 20th century. He initially worked as a servant for an aristocratic British family before securing an apprenticeship as a painter. He faced profound isolation and racism while trying to build a stable life and legacy for his family.

Big Red is a drummer who played alongside Joss for the last ten years, eventually becoming his fierce protector and closest friend. He remains completely unbothered by the media frenzy regarding Joss's biological sex, concerning himself entirely with the loss of his friend and the abrupt end to their musical partnership.

Maggie formerly worked as the cleaning lady for the Moody family's London home for a two-year period. She holds deep affection for the family because of their generous treatment of her, though the promise of financial compensation eventually persuades her to share her observations with a reporter.

May is Joss's childhood playmate from his early years in Scotland. She has maintained a long-dormant romantic affection for her childhood friend and quickly realizes that the opportunistic reporter questioning her is purely self-serving.

Dr. Krishnamurty is the coroner who attends to Joss's body immediately after his passing. She approaches her job with clinical professionalism, removing Joss's chest bandages and officially recording him as female on the death certificate.

Mohammad is a registrar of legal documents who handles Joss's death certification. He acts as a pragmatic, polite British professional who respectfully allows Millie to register the death under the name Joss Moody despite the obvious discrepancy with the provided birth certificate.

Albert is a dedicated funeral director who takes great pride in comforting grieving families through difficult transitions. He experiences a rare moment of professional shock upon discovering Joss's physical characteristics and must delicately manage the situation when Colman arrives to view the body.

Originally named Ruth, Melanie is Colman's former girlfriend. She learned to play the trumpet under Joss's enthusiastic tutelage, but her relationship with Colman ended abruptly after she expressed an intense romantic attraction to Joss's gentle masculinity.

Sammy is Colman's friend who earned Joss's favor by learning to play the trumpet, inadvertently causing Colman to feel inadequate. He serves as a voice of reason, explicitly advising Colman not to make impulsive decisions regarding his father's legacy.

Sarah is Sophie's sister, who was heavily favored by their family while they were growing up. Her perceived status as the perfect child fuels Sophie's lifelong jealousy and drives her ruthless professional ambition.