The family tree - which contains the only direct mention of Jane - indicates she was the middle daughter. She had an older sister, Beth, and a younger sister, Mary. Jane was presumably born sometime before 1937, the year Mary was said to have been born. Her mother and father, Ian Kennedy, lived in England, but Jane presumably emigrated to America at some point. She married a man named Riley Trevor and had a daughter, Gwen, who went on to marry Ted Lennox and had a daughter, Gillian. Jane's husband died some time after her granddaughter was born. It is unknown if Jane herself is still alive or not. Gillian eventually discovered her heritage as a witch in the novel Dark Angel and took her rightful place among the Harmans.
Jane is an English form of the Old French name Jehanne, a feminine form of John, meaning "God is gracious/merciful".
- Jane's father's name is also derived from the name John, Ian being the Scottish form of John.
- Jane's surname should actually be Harman, due to her being a witch, though as she does not know she is a witch she is known as Kennedy, and later Trevor following her marriage.