She is principally known as the author of Sally Wister's Journal, written when she was sixteen; it is a firsthand account of life in the nearby countryside during the British occupation of Philadelphia in 1777 and 1778.

John Wister adopted the Quaker faith and became a successful wine merchant and landowner; he built the house now known as Grumblethorpe in Germantown as a summer home in 1744.

[5] Her writings show some knowledge of French and Latin, and she was clearly familiar with the literature of her time, particularly poetry, and especially Alexander Pope.

[6] It was at the Benezet school that young Sally met the future historian and memoirist Deborah Norris, whom she called Debby.

With the fall of Philadelphia seen as imminent, many Philadelphians fled the city, and Wister's family of seven moved to North Wales, Pennsylvania, home of Hannah Foulke,[9] a widow whose son had married a sister of Lowery Wister[10] and whom Sally knew as "Aunt Hanna[h]"[11] The main house is located a few hundred meters east of Wissahickon Creek, where the Penllyn station has been built; at the time, the Foulkes' mill was nearby.

The battles of Germantown, Whitemarsh, and Barren Hill were fought relatively close to North Wales, but the Wisters remained safe, although there were moments of trepidation.

"[21] While they avoided battles, the inhabitants of the Foulke farm saw many troop movements, and a substantial number of Continental Army officers were billeted in the house, or visited those who were.

Visitors included General William Smallwood, commander of the Maryland troops, who made the house his headquarters, Colonel James Wood of Virginia, and Major Aaron Ogden of New Jersey.

[20] On June 19 comes word that the occupying army has left; the Continentals depart in pursuit, and Sally, "think[ing] of nothing but returning to Philadelphia", concludes her journal.

[36] He returned to Maryland, married a woman named Sally,[37] and died "from the lingering effects of the hardships of camp life"[38] in 1793.

[23] According to The Athenaeum: There is a charmingly light touch about the journal which makes us regret that Sally never took to novel-writing; she might have been an American Miss Burney.

[47] Benjamin Rush noted her death in The Philadelphia Gazette on April 25, 1804, lauding her "prudence, virtue, piety, and eminent acquirements".