During the Warring States period in China, Xin and Piao are two brother-like youngsters who dream of becoming Great Generals, despite their low status as orphaned slaves. One day, they encounter a man of nobility, who gives Piao an opportunity to undertake an important duty within the state of Qin's royal palace. Parting ways, Xin and Piao promise each other to one day become the greatest generals in the world. However, after a fierce coup d'état occurs in the palace, Xin meets with a dying Piao, whose last words spur him into action and lead him to encounter the young and soon-to-be king of Qin, Zheng Ying.

Although initially on bad terms, Xin and Zheng become comrades and start on a path filled with trials and bloodshed. Zheng's objective is to bring all the warring states under Qin, and Xin seeks to climb to the very top of the army ranks. Against a backdrop of constant tactical battle between states and great political unrest, both outside and within the palace, the two endeavor towards their monumental ambitions that will change history forever.

In 2013, Kingdom was awarded the 17th Annual Tezuka Osamu Cultural Grand Prize. As of December 2024, the series has sold over 110 million copies.

On December 12, 2012, the series won a Guinness World Record for manga written by the most people. The record was made possible due to its Social Kingdom Campaign, where artists, fans, and voice actors redrew the entire 26th volume. Each participant picked and redrew one frame; the top 100 would be given a special edition of the manga. Eiichiro Oda (One Piece), Masashi Kishimoto (Naruto), Hirohiko Araki (JoJo no Kimyou na Bouken), and many others were among the participants.

A live-action movie of Kingdom was released on April 19, 2019, a second one on July 15, 2022, a third one on July 28, 2023, and a fourth one on July 12, 2024.

Kingdom has been published in English by VIZ Media under the VIZ Signature imprint since November 11, 2025.