Following the death of his father when he was eight years old, Gregory's education was conducted by Principal Chalmers, his grandfather, and his half-brother James, a professor of medicine.

[1] In 1754 the family moved to London and they entered the social circle of John Wilkes, Charles Townshend, George Lyttelton and Elizabeth Montagu.

[2] The paper he presented there were later collected and published anonymously in A Comparative View of the State and Faculties of Man, with those of the Animal World (1765).

In what would become his most famous publication, Gregory wrote A Father's Legacy to his Daughters after the death of his wife in 1761 to honour her memory and record her thoughts on female education.

Originally Gregory meant only to give the text to his daughters, but his son James published it in 1774; it became a best-seller, going through many editions and translations.

[4] The text advises parents and women on religion, moral conduct, friendship and interactions with men, with a focus on marriage.

Mary Wollstonecraft would later attack these principles in A Vindication of the Rights of Woman (1792), arguing that Gregory's advice amounted to nothing more than deceit on the part of women.

Two years later Gregory was appointed the first physician in Scotland to George III and made a member of the faculty of Edinburgh University.

He is buried in Canongate Churchyard but the plot bears only the name of his son, James, also a prominent doctor and Professor of Medicine.