Diane went to Jenny von Slaniker's "Back From Mono" party in 1985 and met Will, who had just broken up with Grace after coming out, and was upset and drunk. Diane says she was immediately attracted to him because he was "cleaner" than everybody else, running the bong through the dishwasher. They danced to Dead or Alive's "You Spin Me 'Round" and eventually ended up having sex on her futon. Diane admits that this is the only time she ever achieved an orgasm in her life. When she woke up the next morning, Will had left but not before baking her cookies and doing a load of her laundry. Will also took her roommate's Bennetton sweater, which Diane got blamed and went to student court for.
A year later, Will saw her again at D'Agostino's while he was talking to Grace, though Diane did not see him because he hid behind the groceries out of shame. By this time, she had short red hair.
Later in life, she dates Leo for a year and a half. He says that their families have become close he used to call her parents "Papa Tom" and "Mama Joanne" and she has a drawer at his apartment.
After Leo and Grace got married, he meets Diane in the subway and invites her to dinner with her friends, where she reunites with Will. They finally settle things after Will apologizes to her, but Grace becomes increasingly jealous knowing that Diane slept with Will right after he could not do it with her. Diane miserably confesses that she is still not over Will and names the puppy Karen and Jack give to her after him.
- Diane is played initially by Lisa Borgnes who worked on the show and was friends with series creators Max Mutchnick and David Kohan. She was later replaced by Mira Sorvino.
You're a gorgeous redhead, I'm an adorable blonde. But we know we have something in common... brown hair. — meeting Grace