She was likely born at the Swynford manor of Kettlethorpe in Lincoln. Her surname probably reflects her father's lordship of Beaufort in Champagne, France, where she might also have born. In 1391, at the age of twelve, Joan married at Beaufort-en-Vallée, Anjou, Robert Ferrers, 5th Baron Boteler of Wem, and they had two daughters before he died about 1395.

Joan died on 13 November 1440 at Howden in Yorkshire. Rather than be buried with her husband Ralph (who was not buried with his first wife, though his monument has effigies of himself and his two wives) she was entombed next to her mother in the magnificent sanctuary of Lincoln Cathedral. Joan's is the smaller of the two tombs; both were decorated with brass plates — full-length representations of them on the tops, and small shields bearing coats of arms around the sides — but those were damaged or destroyed in 1644 during the English Civil War. A 1640 drawing of them survives, showing what the tombs looked like when they were intact, and side-by-side instead of end-to-end, as they are now.