Hattie is the mother of Philip Banks and Hilary, Carlton, Ashley and Nicky's paternal grandmother. Hattie loves her grandchildren, and also bonds with Will, whom she seems to share love of fun with. She also is the only one who calls Phil "Zeke", which was his nickname growing up. She and her husband behave very much like rural Southerners, having owned a farm in North Carolina. They are both down to earth, calm and have good values.
Her first appearance is in the episode, Not with My Pig, You Don't, when she appears alongside her husband Joe. When Phil is honored with a prestigious award, he believes people want to hear stories about guys rising up from the streets and graduating from college. His parents' recollections of his time on the farm are an embarrassment to him, because it makes him seem like a sheltered country bumpkin. When the press gets wind of his early life, it becomes a hit, but Phil is enraged. Will tries to get Phil to be proud of his early accomplishments, such as being the first black boy to get elected president of the local chapter of the Future Farmers. Phil, coming to realize there is no single or "right" way to success, gives a rousing speech at the awards dinner talking of his time on the North Carolina farm, but more importantly being gracious for both his parents being on hand to raise him, which not everyone gets.
Hattie goes on to make several more appearances, most of them dealing with her relationship with her son and Will, who always tries to smooth the situation between them when it gets negative. She is a widow from "Granny Gets Busy" onward.
She appears in a total of 6 episodes. Will calls her "Granny", despite the fact that she is not Will's biological grandmother.