Mallory was a public school teacher.
She was romantically interested in Sam Seaborn. Their relationship was a source of humor for her father, Leo McGarry, and First Lady Abigail Bartlet. She and Sam drifted apart after the news broke about his relationship with a law student who was also a high-end call girl. She dated a professional hockey player named Richard Andreychuk. Sometime before her father's death, she married and had a son.