Iris is the elder daughter of Norval Chase, who was himself the heir to the Chase estate. She personally guides us through an account of the Chase family history, and, most notably, the decline in fortune that led Iris to marry the wealthy industrialist Richard Griffin, as well as the fallout of that decision (up to and including her sister's suicide). She is also the narrator of all the events that take place in the novel's "present"; that is, the months leading up to her own death. Lastly, Iris is the author of the autobiographical novel-within-a-novel, The Blind Assassin, which she publishes under her sister's name.

The fact that Iris conceals this book's true authorship from us for most of the novel makes her, on some level, an unreliable narrator (as does her failure to tell us about her affair with Alex, and Aimee's real parentage). However, in light of the questions that Atwood's novel raises about the nature of truth, we could read these omissions as true in "what Laura would have called the spiritual sense" (512). Iris describes Laura as her "collaborator" in writing the book, and there are elements of its story that reflect Laura's life just as much as they do Iris's; perhaps Iris's decision to hide the truth is a way of ensuring that we read both the novel-within-a-novel and the novel itself as belonging equally to Laura (513).