Njal is a wise, even-tempered 10th-century Icelandic farmer and legal expert. He possesses the gift of second sight and frequently offers prophetic warnings and legal advice to his friends and neighbors. Despite his intelligence and respected position in society, he cannot grow a beard, a trait his detractors occasionally mock to bruise his ego. He strongly prefers peace and legal settlements over the traditional Scandinavian practice of blood feuds.

Gunnar is a highly capable warrior known for his physical prowess, courage in battle, and loyalty as a friend. He represents idealized Icelandic masculinity, earning wealth and honor through raiding and trading abroad before settling down. Despite his martial skills, he is fair, even-tempered, and expresses discomfort with killing, often relying on Njal's legal strategies to navigate conflicts and avoid bloodshed.

Hallgerd is the tall, beautiful, and temperamental wife of Gunnar. She manages her household with a firm hand and fiercely guards her sense of honor. Prone to holding grudges, she manipulates the men around her to carry out violent acts of retaliation when she feels disrespected, caring little for the legal or social consequences.

Skarphedin is the eldest son of Njal and Bergthora. He is fearless, brazen, and inherently violent, often striking an intimidating figure in Icelandic society. He struggles to adhere to his father's peaceful, legalistic methods, preferring swift physical retaliation against perceived insults or threats to his family.

Bergthora is Njal's strong-willed and authoritative wife. She actively manages their large farming household, directing the servants and maintaining order. She is deeply protective of her family's honor and fiercely engages in a bitter feud with Hallgerd, readily ordering retaliatory strikes when provoked.

Mord Valgardsson is a cunning, wealthy, and deeply envious man. Driven by jealousy of highly respected men like Gunnar, he uses deceit, legal manipulation, and false friendships to orchestrate conflicts among his peers. He constantly seeks to prove his masculinity through behind-the-scenes treachery rather than direct combat.

Hoskuld Thrainsson is Njal's beloved foster son. He grows up strong, handsome, kind, and exceptionally good-tempered. As a newly established godi (chieftain), he acts as a peacemaker and refuses to harbor ill will toward his foster family, prioritizing honor and virtue over petty squabbles.

Flosi is a prominent and wealthy godi with a strong sense of duty to his extended family. He values his public honor and operates within the bounds of Icelandic law, though he finds himself heavily pressured by the strict codes of blood vengeance when his kin are slighted.

Kari is a heroic warrior and a member of Earl Sigurd of Orkney's retinue. He acts as a loyal and formidable ally to the Njalssons, joining them on raiding expeditions before traveling with them back to Iceland. He firmly aligns himself with Njal's household through marriage and vows to stand by them in their disputes.

Hrut is an intelligent chieftain who spends time in Norway serving the king. He possesses prophetic insight, correctly predicting the trouble his niece Hallgerd will cause. His own marital prospects are complicated by a curse placed upon him by a Norwegian queen, leading to lasting personal distress.

Unn is an Icelandic woman who seeks a divorce from Hrut due to the lack of physical intimacy in their marriage. She struggles financially after squandering her inheritance but utilizes her connections to Gunnar and Njal to reclaim her property through the complicated legal system.

Kolskegg is Gunnar's fiercely loyal brother. He serves as Gunnar's constant companion in battle, fighting skillfully alongside him during ambushes and feuds. He supports Gunnar unconditionally, navigating the violent consequences of their regional rivalries.

Hoskuld is a prominent chieftain who arranges his daughter Hallgerd's various marriages. He often navigates the legal fallout of her turbulent relationships, paying compensation to avoid outright warfare when her husbands meet untimely ends.

Thrain is Gunnar's uncle, a wealthy and respected man who frequently travels abroad. He forms an alliance with Earl Hakon in Norway but causes significant tension with Njal's sons by harboring outlaws and making slanderous remarks about them upon returning to Iceland.

Hall of Sida is a virtuous, highly respected chieftain who plays a crucial role in Iceland's conversion to Christianity. He acts as a voice of reason and moderation at the Althing, consistently advocating for peace, humility, and legal settlements over continued bloodshed.