Leif Erickson is a retired traveler and adventurer who resides in Greenland. He is one of the few individuals to have successfully reached Vinland, a land that holds great significance in the story. He was a close friend of Thors Snorresson, and after Thors's death, he becomes deeply connected to his son, Thorfinn. Leif owns a farm on Greenland but has largely abandoned its care, focusing his energy on his legacy of exploration and his bond with Thorfinn's family.

In terms of personality, Leif is kind-hearted and often cheerful, though he can come across as brash. He is inherently loyal and possesses a strong sense of duty, which drives him to spend eleven years searching for Thorfinn after the boy goes missing. This quest is framed as a way of repaying a debt to Thors. While he is known for his adventurous spirit and generosity, the character also displays more complex and problematic traits, including certain conservative social views that add nuance to his personality and make him a layered figure rather than a simple hero. In his youth, he was known to boast about his abilities as a warrior, though others around him saw him as more of a harmless adventurer than a formidable fighter.

Leif's primary motivation is his devotion to his friends and his desire to guide the next generation. He acts as a catalyst for Thorfinn's dream of finding Vinland, serving as both an inspiration and a source of practical knowledge about the land. His role in the story is that of a guide and mentor, helping Thorfinn understand and embrace the peaceful ideals that his father, Thors, held. He is instrumental in setting the narrative's central goal into motion.

His key relationships are with Thors and Thorfinn. His friendship with Thors defines his past, while his relationship with Thorfinn defines his present. He is a father figure to Thorfinn, one who contrasts sharply with the violent figures Thorfinn encounters during his quest for revenge. Leif's loyalty to the Snorresson family is unwavering.

Over the course of the story, Leif's character development is marked by a shift from a relatively boastful and adventure-seeking youth into a mature, patient, and deeply loyal elder. His experiences have tempered him, transforming him from someone who valued fame and glory into someone who values loyalty, peace, and the well-being of those he cares for. His understanding of the world evolves from one of conquest and discovery to one of hope and atonement.

Regarding his abilities, Leif is not depicted as a great warrior. Instead, his strengths lie in his exceptional skill as a navigator and explorer. He is a master sailor and a knowledgeable woodsman, well-versed in the challenges of transatlantic travel and survival in harsh, uncharted lands. His most notable ability is his experience and the detailed knowledge he possesses of Vinland and the routes to reach it, a knowledge that ultimately becomes the foundation for Thorfinn's own journey.