Kay stated in an interview that her novel was inspired by the life of Billy Tipton, an American jazz musician who lived secretly as a transgender man in the mid-twentieth century.
After his death, it is revealed that his biological sex was female, causing a news rush and attracting paparazzi, leading his widow, Millie, to flee to a vacation home.
He vents his rage about his father's lie by uncovering Joss's life to Sophie, an eager tabloid journalist craving to write the next bestseller.
After time, and a visit to Joss's mother Edith Moore, Colman eventually finds love for his father muddled together with his rage.
All the while, Millie deals with her grief and the scandal in private turmoil at the Moodys' vacation home, and a variety of characters whose paths have crossed with Joss's give accounts of their memories and experiences.
Most of these memories are set in Glasgow in the 1960s, referring to locations such as The Barrowlands music venue at the start of Joss and Millie's relationship and their early marriage.
Although much of the story takes place in London where the Moodys lived, it jumps back and forth between the city and the Scottish seaside home where Millie goes to escape the scandal and grieve in peace.
In addition, chapters told from a third-person omniscient narrator contribute to the story, each focusing on a different minor character, such as the funeral director or Joss's drummer.
Colman feels that his male identity is being questioned after his father's death because he loses a sense of attachment to the safety and assurance from the patriarchal culture and system.
Colman's relationship with sex appears affected by the trauma of discovering that his father had female genitalia, but may also be linked to the possessive nature of the patriarchal system.
Amidst a strong duality of themes (notably male and female, Black and white) jazz on the other hand offers freedom and detachment from social norms and constrictions.
The narrative reveals people's reactions to the discovery after Joss' death, shown through their disorientation, disgust or just general transphobic comments.
[10] Transphobia is shown against Joss and to all those he knew as well, starting with the disregard held for his family and friends' opinions of him, making it all the more difficult for him to be defended when he is not there to do it himself.
After his death he is treated as "a Black queer monstrosity that can be met only with derision and turned into spectacle",[7] and the only thing Millie continues to do is refer to him using male pronouns.
The novel also explores the fluidity of gender perception, as characters frequently describe Joss's face transforming, becoming more feminine upon learning his identity as transgender, despite their previously perceiving him wholly as male.
[12] In an article for the Boston Phoenix, David Valdes Greenwood wrote that "in the hands of a less graceful writer, Jackie Kay's Trumpet would have been a polemic about gender with a dollop of race thrown in for good measure.
Spare, haunting, dreamlike", and the San Francisco Chronicle commented that "Kay's imaginative leaps in story and language will remind some readers of a masterful jazz solo".
"[16][17] Writing about the novel he says, "We have to consider the long intertwined histories of genital policing and sexual violence Black folks have been subject to during the Middle Passage and plantation slavery and since."
Copyright 1998 by Jackie Kay, Trumpet was originally published by Picador (Great Britain) in 1998, and Pantheon Books (New York).