Good Boy — Characters & Cast

Initially motivated by a desire to clear his name and protect those around him, his motivation deepens into bringing down systemic corruption regardless of personal cost.

Begins as a washed-up, impulsive former Olympic boxing gold medalist plagued by a sense of failure and early-stage punch-drunk syndrome. Through leading the SCIT, he transforms into a mature, selfless team pillar who learns to rely on his teammates rather than bearing every blow alone.

Starts with seeking a quiet life and fulfilling her father's police legacy; evolves into fiercely guarding her found family and fighting corruption with precise evidence.

Dubbed the "Shooting Goddess," she abandoned competitive shooting following a traumatic public scandal and her father's tragic death. Initially emotionally detached, she opens her heart to Dong-ju and steps up as the team's calm tactical anchor.

Driven by insatiable greed, power over institutions, and contempt for honest effort.

Appears publicly as a modest, diligent Grade 7 Customs Service civil servant while secretly operating as the kingpin of a massive smuggling cartel. He remains unrepentant and manipulative throughout, growing increasingly chaotic and ruthless as the SCIT dismantles his empire.

Moves from strict adherence to administrative rules to understanding that true justice requires stepping into the ring alongside his comrades.

A former Olympic fencing silver medalist and strict Internal Affairs sergeant. Initially conflicted due to past feelings for Han-na and distrust of Dong-ju's wild methods, he overcomes his jealousy to become the squad's legal shield and tactical strategist.

Evolves from self-preservation to becoming a true protective father figure for the entire "Olympic Avengers" squad.

A former Asian Games wrestling medalist and grizzled SCIT Team Leader. Tired of police politics and fearing for his family's safety, he initially takes a cautious approach, but eventually risks his career to protect his younger officers.