Joan Haslip was born to a father of Irish descent and an Austrian mother. She grew up in Florence, Italy, part of the British expatriate community there, and was privately educated. She also travelled widely from a young age and learned to speak several languages. She became a journalist and worked from 1929 to 1939 as a "sub-editor" at the London Mercury, contributing reviews and other pieces, including some poetry. She began her career as an author at this time by writing two novels, Out of Focus (1931) and Grandfather Steps (1932). During World War II, she was an editor in the Italian section of the European Service of the BBC. She's best known for her popular and critically acclaimed biographies, including those of Marie Antoinette, Empress Elisabeth of Austria, and Charles Stewart Parnell. The Times of London said of Joan Haslip that "she had an eye for the romantic, the dramatic, the picturesque." Joan Haslip was a Fellow of the Royal Society of Literature. In addition to her writing, she also lectured on Italian subjects. In her later years, she lived at a remote house in Bellosguardo, on a hill to the south of the Arno River, where she maintained a lively social life with old friends in the area.