Jason is the protagonist, a young man noted for his beauty. He is the nephew of King Pelias of Iolkus, and Pelias considers him a danger to his throne. Jason is adventurous and loyal to his crew, but at times he lacks confidence and can become quickly discouraged. At pivotal moments, he finds leadership anxiety provoking and only succeeds at his quest because of Medea’s intervention. In his characterization and epithets, Jason explicitly contrasts with both the Iliad’s Achilles and the Odyssey’s Odysseus. His epithet is amekhanos, meaning “without resources;” one of Odysseus’ epithets is polymekhan, meaning “of many devices.” Contrary to Achilles, Jason does not jump eagerly into battle. For example, Polydeukes volunteers to face Amykos, rather than Jason. When the Argonauts fight the Colchians, Jason shows up at the end but is unnecessary, as the Argonauts have defeated them without him.

The hero Jason most closely resembles is Paris, the Trojan prince who, with Aphrodite’s help, brings Helen (and her treasure) from Sparta to Troy. In Apollonius, Aphrodite is also the patron of Jason. She sends Eros to inflict Medea with love for the Hellenic hero so that she will engineer a plan for his success.