She appears first in the episode "Sucker Punch" playing pool with Harvey, whom she has had a history with. She is revealed to be a former lawyer who worked for Pearson Hardman and was not on friendly terms with Jessica Pearson. She is brought on as a jury consultant to help Harvey and the firm with battling out their lawsuit.
Later on, she appears in "Blind-Sided" where she has a date with Harvey, who wanted to celebrate his victory. Unfortunately, she had her niece Olivia over, the two spend an evening together and reconcile. They share a surprising kiss, and it is disclosed that Harvey has serious intentions towards her, unlike other women. At the end of the episode, when Harvey comes to Zoe for the second time, it is revealed that her brother has cancer, and she's going to raise Olivia outside of New York, devastating Harvey.
The last mention comes from "War". Donna claims that Harvey let Zoe go and did not fight enough for her. He responded that she left him, and he did not want to replace Olivia's dad.