The plot follows Henry Hill, a young man from a working-class Brooklyn neighborhood who becomes seduced by the power, luxury, and glamour of organized crime. From an early age, Hill is drawn into the local mob life, becoming a devoted protégé of James "Jimmy the Gent" Conway, a smooth-talking, well-dressed gangster, and the violent and unpredictable Tommy DeVito. Starting off with small-time jobs and errands for the Lucchese crime family, Henry's ambition drives him to take on bigger and riskier ventures, enjoying the perks and lifestyle that come with being an associate in the underworld.

As Henry climbs the ranks within the mob, his personal life and ties to the criminal world become more complex. He falls in love with Karen, a Jewish girl from the Five Towns, and they soon marry. Despite his wife's initial obliviousness to the criminal activities, she eventually becomes complicit in his lifestyle. The trio of Henry, Jimmy, and Tommy continue their ascent, engaging in high-profile robberies and other lucrative crimes. Their brotherhood thrives under the wing of the mob's protection but soon begins to fray as their actions draw increased attention, both from law enforcement and rival mobsters. Success brings wealth and power, but also distrust and the constant threat of betrayal or violence. As the stakes get higher, the bonds of loyalty are tested, and Henry's life as a gangster becomes increasingly unstable and dangerous.