Moll, a dower slave, was the nanny for Martha Custis's four children by her first marriage (two of whom died young). Moll was 19 when she came to Mount Vernon upon the marriage of the widow Martha Custis and George Washington in January 1759, and so was born around 1739. She nursed Mrs. Washington's daughter Patsy until the sickly girl's death at age 17 in 1773. Moll appears to have never married or had children of her own, although at one point historians mistakenly assumed that she had been Austin's wife.
Moll was described as Martha Washington's personal maid in the New York and Philadelphia households, but she probably was primarily the nanny to the First Lady's two youngest grandchildren. When Moll arrived at the President's House in 1790, it is likely that she slept in one of the divided rooms over the kitchen with either 11-year-old Nelly or 9-year-old G. W. Parke Custis.
Moll returned to Mount Vernon in 1797 at the end of Washington's presidency. She is recorded as standing at the door of Washington's bedroom as he died on December 14, 1799. After Martha Washington's death in 1802, Moll probably became part of the household of one of the Custis grandchildren.
One of them later described her as "Mammy Molly, my old Nurse, who always overwhelm'd me with caresses when I visited Mt Vernon, & from whom I was ever afflicted to part --"