Gregor is the main character of the story. He works as a traveling salesman in order to provide money for his sister and parents. He wakes up one morning finding himself transformed into an insect. After the metamorphosis, Gregor becomes unable to work and is confined to his room for the remainder of the story. This prompts his family to begin working once again.
The name "Gregor Samsa" appears to derive partly from literary works Kafka had read. The hero of The Story of Young Renate Fuchs, by German-Jewish novelist Jakob Wassermann (1873–1934), is a certain Gregor Samsa. The Viennese author Leopold von Sacher-Masoch, whose sexual imagination gave rise to the idea of masochism, is also an influence. Sacher-Masoch (note the letters Sa-Mas) wrote Venus in Furs (1870), a novel whose hero assumes the name Gregor at one point. A "Venus in furs" literally recurs in The Metamorphosis in the picture that Gregor Samsa has hung on his bedroom wall. The name Samsa is similar to "Kafka" in its play of vowels and consonants: "Five letters in each word. The S in the word Samsa has the same position as the K in the word Kafka. The A is in the second and fifth positions in both words."
Greta is Gregor's younger sister, who becomes his caretaker after his metamorphosis. Initially Greta and Gregor have a close relationship, but this quickly fades. While Greta initially volunteers to feed him and clean his room, she grows increasingly impatient with the burden and begins to leave his room in disarray out of spite. She plays the violin and dreams of going to the conservatory, a dream Gregor had intended to make happen; Gregor had planned on making the announcement on Christmas Eve. To help provide an income for the family after Gregor's transformation, she starts working as a salesgirl.
Mr. Samsa is Gregor's father. After the metamorphosis, he is forced to return to work in order to support the family financially. His attitude towards his son is harsh; he regards the transformed Gregor with disgust and possibly even fear.
Mrs. Samsa is Greta and Gregor's mother. She is initially shocked at Gregor's transformation; however, she wants to enter his room. This proves too much for her, thus giving rise to a conflict between her maternal impulse and sympathy, and her fear and revulsion at Gregor's new form.