Gintoki Sakata is the central protagonist of his narrative, a former rebel samurai navigating life in a version of Edo-period Japan that has been transformed by an invasion of extraterrestrials known as the Amanto. He is a tall man in his late twenties with a lean build, famously characterized by his unruly natural perm of silver-white hair and half-lidded, listless eyes that often give him an air of perpetual apathy. His typical attire consists of a loose, traditional white kimono with blue wave-like patterns, worn over a black undergarment, and completed with wooden geta sandals. His primary weapon is a wooden bokuto, which he humorously purchases from a television shopping channel, yet he treats this seemingly mundane sword as if it were a legendary blade.

Gintoki's personality is a stark contrast of extremes, blending profound laziness and childishness with unwavering strength and moral integrity. In his daily life, he is a slacker who is constantly short on money for rent, an obsessive sweet-tooth who has been warned about developing diabetes, and an ardent fan of Weekly Shonen Jump magazine. He displays cowardice in trivial situations, has a well-documented fear of ghosts and the dentist, and often shirks responsibility in favor of playing pachinko or napping. However, this frivolous exterior masks a deeply caring and protective individual who lives by his own interpretation of the samurai code. When his friends or the vulnerable are threatened, his demeanor changes completely; he becomes a serious, decisive, and formidable warrior willing to risk his life without hesitation.

His past is a wellspring of his present motivations. As an orphaned child, he survived by scavenging from battlefields until he was taken in and educated by the kind-hearted teacher, Shoyo Yoshida. Alongside his fellow students, Kotaro Katsura and Shinsuke Takasugi, he later fought in the Joui War against the Amanto, where his ferocity and silver hair earned him the legendary moniker Shiroyasha, or White Demon. The war ended in tragedy when Gintoki was forced to personally execute his beloved master to save the lives of his comrades, an act that left him with immense trauma and guilt. After the war, he distanced himself from his former life and founded the Yorozuya, a small, two-person odd-jobs agency run out of the second floor of a snack house owned by his landlady, Otose.

His role in the story is centered on running the Yorozuya and the found family he builds there. Initially working alone, he is soon joined by Shinpachi Shimura, a bespectacled boy who wishes to learn the way of the samurai, and Kagura, a super-strong alien girl from the Yato warrior race. Together, they take on any request from walking pets to saving the world, all while struggling to pay their rent. These companions form the core of his new life, replacing the one he lost in the war. His key relationships are defined by this past and present: he shares a deep bond with his war comrade Kotaro Katsura, a lasting ideological enmity with the vengeful Takasugi, and a perpetual rivalry-friendship with Toshiro Hijikata of the Shinsengumi police force. He is also fiercely protective of Otose, whom he promised to defend after eating food offerings meant for her late husband.

While he shows minimal superficial change, Gintoki's development is a deep emotional arc of confronting and reconciling with his past. Over the course of the story, the trauma of killing his master and losing his comrades is explored, forcing him to face former friends who have become enemies. He evolves from a man isolated by his guilt into a full-fledged leader and patriarch of his new family, demonstrating that he has learned to protect those around him without being consumed by the same loss. As a warrior, he is a preternaturally skilled and experienced swordsman, capable of defeating superhuman opponents while armed only with his wooden sword. His fighting style is described as rough and wild, yet refined and highly effective, relying not just on raw power and speed, but also on keen intuition, tactical acumen, and even trickery to win.