Mallt was the daughter of unknown parents. The date and place of her birth have not been found.
Her husband was Tudur ap Goronwy Fychan. They were married, but the date and place have not been found. Their seven known children were Goronwy ap Tudur (?-1382), Rhys ap Tudur (?-<1412), Ednyfed ap Tudur (?-c1382), Gwilym ap Tudur (?-1413), Angharad verch Tudur (?-?), Angharad verch Tudur (?-?) and Margred verch Tudur (?-?).