Sally Hemings's working life was shaped by enslavement in the household of Thomas Jefferson. Her labour is documented mainly through Jefferson's records, family testimony and the accounts of others; no writing in her hand is known. She worked as a domestic servant, lady's maid and seamstress, positions requiring skill and trust while leaving her subject to the authority and coercion of an enslaver.

In 1787 she accompanied Jefferson's daughter Maria to France and joined the household in Paris. There she attended Maria and Martha Jefferson and probably received further training in needlework and the care of clothing. Records show purchases of clothing and occasional wages, but payment in Paris did not erase the unequal relationship. French law offered a possible route to freedom that was unavailable to her in Virginia.

According to the testimony of her son Madison, Hemings initially resisted returning to America and agreed only after Jefferson promised privileges and freedom for her children when they reached adulthood. This account is central evidence for a consequential negotiation, although its details cannot be independently reconstructed from her own words. She returned in 1789 and continued domestic and sewing work at Monticello. The evidence supports Jefferson's paternity of her children, within a relationship in which legal ownership made freedom of consent profoundly unequal.

Her household responsibilities included the care of Jefferson's chamber and wardrobe as well as work for her own family. Several of her children gained freedom during Jefferson's lifetime or under his will. Hemings herself was not formally emancipated by him, but after his death she lived in Charlottesville with her sons and was allowed to remain free in practice. Her life should not be reduced to the label of a president's mistress. Her activities included skilled labour and efforts to secure freedom for her children under conditions that denied her legal control over work and movement.