The unnamed American narrator is an editor and obsessive follower of the deceased Romantic poet Jeffrey Aspern. He travels to Venice under a pseudonym to locate a rumored cache of the poet's personal letters. Presenting himself as an honorable, eccentric writer seeking a quiet garden, he uses his wealth and charm to rent rooms in a decaying Venetian palace. His intense reverence for Aspern frequently clouds his ethical judgment, driving him to manipulate the women who live there.

Juliana is the elderly, fiercely reclusive former lover of Jeffrey Aspern, currently living in isolation in a dilapidated Venetian palace. She acts as the heavily guarded keeper of the poet's past, using her sharp intellect to maintain control over her environment and secrets. Though physically frail, she commands an exorbitant price for rent, driven by a desire to secure financial stability for her niece. She constantly evaluates the Narrator's wealth and intentions, turning their arrangement into a quiet battle of wits.

Tita is Juliana's middle-aged, unmarried niece who lives a thoroughly secluded life in the Venetian palace. Plain in appearance and mild in demeanor, she functions primarily as her aunt's caretaker and obedient proxy. She lacks worldly experience and often recites speeches rehearsed by her aunt, though she occasionally betrays a quiet longing for the outside world and human connection.

Jeffrey Aspern is a deceased, canonical Romantic poet whose legendary body of work commands intense worship from his modern followers. Though he never physically appears, his past romance with Juliana Bordereau created a rumored archive of personal papers that drives the plot. His ghostly presence looms over the characters, dictating the motivations of the living.

Mrs. Prest is an American expatriate who has lived in Venice for fifteen years. She acts as a practical sounding board for the Narrator, playfully teasing him about his obsession with the dead poet. It is her suggestion that the Narrator pose as a lodger to infiltrate the Bordereau household, providing the catalyst for the entire scheme.

John Cumnor is a literary editor who shares the Narrator's intense devotion to Jeffrey Aspern. He previously wrote to the Bordereaus inquiring about the papers, only to be firmly rebuffed with a denial of their existence. His failure prompts the Narrator to employ deception rather than direct inquiry.