Mildred Grayson is Susan's mother, and Daniel's grandmother. She is known as the iron matriarch of Grayson Hall. Cecilia said that Mildred's countenance is slightly more foreboding than Lady Catherine de Bourg from Pride & Prejudice, but Cecilia understood Mildred. Underneath that formidable veneer, was a passionate woman.

Mildred was a quiet and shy girl who loved to bake when her family arranged for her to marry Reginald Grayson. In order to assume her role as the Grayson Hall matriarch, she made herself into someone else.

Although she didn't always show it, Mildred loved her children, Susan and Edward, and her grandson, Daniel, very much.

She is greatly saddened by the death of Cecilia, and is never quite the same woman afterwards.