The former Catherine Spicer of Staten Island and widow of Manson Mingott is Ellen's grandmother. What is most memorable about her is her immense size. Despite her lively eyes and interesting conversation, she lives in an obese body. A widow at 28, she had single-mindedly used her will and ambition to win and maintain a social position, and her attention to values of decency in her private life had won society's approval. She hobnobbed with the fashionable and the corrupt of European society, and she knew intimate friends and admirers on both continents.
Her love for her granddaughter, Ellen, is never in question. She, like Ellen, is a realist and in "cold-blooded complacency" declares that Ellen's life is over after she leaves the Count. Mrs. Mingott sees clearly that Ellen's future is either an unhappy affair with Newland or an unhappy marriage with the Count, and of the two possibilities, the second is more socially acceptable. Catherine knows from vast experience that "socially acceptable," while not always bringing happiness, is far more fulfilling than living on the outskirts of polite society.
She survives the storms of Ellen's decisions and undisputed lack of social etiquette, and she champions Ellen's cause with the family. A realist, she turns to Newland when matters of finance and divorce must be settled. But when Regina Beaufort asks for her backing as the family matriarch over Julius Beaufort's scandalous behavior, it is too much for the old lady. The realist ever, she makes it financially possible for Ellen to live on her own, single, but in charge of her destiny.