Jim is a young black man who flees enslavement upon learning his owner intends to sell him. Driven by the urgent need to reach his ailing mother, he escapes. During his journey, he encounters Huckleberry Finn, who is also fleeing difficult circumstances—specifically his father's abuse. The two form a partnership, building a raft to travel the Mississippi River together.

Jim possesses practical wilderness knowledge that becomes vital for survival during their travels. He offers moral guidance within their relationship, influencing Huckleberry Finn's perspectives through their shared experiences. His actions demonstrate loyalty and a readiness to protect others, prioritizing their safety even at personal risk.

He proves resourceful and resilient in navigating the challenges of pursuit while maintaining focus on reuniting with his family. His character provides stability through practical skills and emotional support throughout their journey.