[4] Her mother was the daughter of Robert Sauders, and her father was the son of the Reverend Henry Jennings of St. Marys County, Maryland.

In the 1760s, she met Thomas Johnson who was a young man recently employed as an apprentice at the land office where her father worked.

[6][9] After serving as an Anne Arundel County Delegate to the Provincial Assembly and as a Congressman in two Continental Congresses, Thomas Johnson was elected by the legislature as the first governor of Maryland in 1777.

[14] Ann Jennings Johnson died on November 22, 1794, at the age of 49 after a period of illness, and only a few months after her husband's retirement from public service.

She was buried at All Saints' Episcopal Church and her remains (along with her husband's) were moved to a new family monument at Mount Olivet Cemetery in 1913.