Alfonso II d'Este (1533-1597) is Lucrezia’s husband, depicted as both refined and capable of violence. He is the basis for the narrator of Robert Browning’s poem "My Last Duchess." The character’s dual nature is shown through his treatment of his wife and his infertility is used as a means to control those around him, including Lucrezia.

Lucrezia’s mother, Eleanora (1522-1562), is a Spanish aristocrat married to Cosimo di Medici. She balances her roles as a conformist and a visionary, managing her household efficiently while fearing the autonomy her daughter represents.

Cosimo (1519-1574) is Lucrezia’s father, portrayed as a patron of the arts with a congenial disposition. He values his daughter Isabella more and is skeptical about Lucrezia, treating her more as a tool for political alliances.

The eldest Medici child, Maria is initially Lucrezia’s roommate, and upon her death, Lucrezia takes her place as Alfonso's betrothed. Maria's qualities highlight Lucrezia's insecurities, as Lucrezia feels inadequate attempting to fill in for her sister.

Lucrezia’s older sister, Isabella, is the favorite child and is portrayed as the epitome of conventional womanhood. Her relationship with her father and her sister frames Lucrezia’s isolation and struggle for individuality. Her suspicious death later ties into the themes of women’s disposability in the novel.

Sofia is an invented character, serving as Eleanora’s nurse and more approachable mother figure for Lucrezia. Her relationship with Lucrezia is intimate and supportive, delaying Lucrezia’s marriage by postponing announcements of her maturation.

Lucrezia’s maid, Emilia, shares a sister-like bond with her and assists her in keeping secrets. Emilia is dedicated, capable, and loyal, allowing her and Lucrezia’s relationship to flourish in a stifling court environment.

Leonello, Alfonso's consigliere, is trusted to handle sensitive matters. He initially seems hostile toward Lucrezia, and later, it's revealed that he is part of a regime of fear alongside Alfonso.

An orphaned Neapolitan cloth-painter, Jacopo shares Lucrezia’s artistic spirit and becomes her confidant and romantic interest. Their shared heritage and bond offer Lucrezia a glimpse of genuine connection beyond her oppressive marriage.

A historical painter, Il Bastianino, exploits his assistant Jacopo's talents while taking credit for the portrait commissioned by Alfonso. He follows the exploitative practices of his time in his interactions with Lucrezia.

Alfonso’s sister, Elisabetta, strives for freedom through a forbidden relationship. She forms a bond with Lucrezia, and her independence signifies a desire for relationships founded on equality.

Nunciata is the less attractive of Alfonso’s sisters who engages in undermining other women and spreading rumors. She thrives on maintaining discord in Alfonso's court, lacking personal purpose.