Kaiji Kawaguchi was born on July 27, 1948, in Hiroshima Prefecture, Japan, and is a highly respected manga artist whose career began while he was still a student. He made his professional debut in 1968 with the work Yoru ga Aketara in the magazine Young Comic, published by Shonengahosha, at the age of twenty-one while attending Meiji University, from which he would later graduate from the Department of Japanese Literature. His early career saw him exploring a variety of genres, but he is most renowned for sophisticated, often politically charged narratives that examine Japan's place in the world.

Kawaguchi's body of work includes numerous titles that have been adapted into other media, and he is credited as the original creator for several anime productions. One notable example is A Spirit of the Sun, a manga series he wrote and illustrated that was serialized in Shogakukan's Big Comic from 2002 to 2010. The story, which depicts Japan's struggle for survival after a catastrophic series of natural disasters, was adapted into a two-episode anime television special produced by the studio Madhouse and directed by Masayuki Kojima, airing on WOWOW in 2006. He is also listed as the original creator for the 1991 anime Ai Monogatari, an anthology film for which he provided the source material. Furthermore, his manga Hard & Loose, which he drew from a story by Marley Carib and serialized from 1983 to 1987, was adapted into the original video anime Shiritsu Tantei Toki Shozo no Trouble Note - Hard & Loose, released in 1992.

Throughout his extensive career, Kawaguchi has demonstrated a remarkable ability to tackle complex and weighty subject matter. His stories frequently involve Japan in high-stakes scenarios, exploring political, military, and social crises that force characters to confront difficult moral choices. His most famous works include The Silent Service, a groundbreaking series about the crew of a rogue nuclear submarine that earned him the Kodansha Manga Award in 1990, and Zipang, a time-traveling drama about a modern Japanese destroyer sent back to World War II, for which he received another Kodansha Manga Award in 2002. Other major titles, such as Eagle, a political thriller set during a U.S. presidential election, and Kūbo Ibuki, a story about a Japanese aircraft carrier, further cement his reputation for weaving meticulous research into compelling, realist dramas.

The artist has cited a significant early influence from cinema, particularly the films of Akira Kurosawa, and from the adult-oriented gekiga style of manga. A pivotal moment in his artistic development occurred during the serialization of Hard & Loose, when his editor suggested he draw characters with larger eyes to better convey emotion. This change, which he initially doubted, ultimately allowed him to more confidently depict Western characters and set stories overseas. He has credited his work on the series Actor, which earned him his first Kodansha Manga Award in 1987, as the foundation for his mature, recognizable style.

Kaiji Kawaguchi holds a significant place in the manga industry as one of its most accomplished and respected creators. His work has garnered widespread critical acclaim, including a total of three Kodansha Manga Awards and two Shogakukan Manga Awards, the latter for A Spirit of the Sun in 2006 and Kūbo Ibuki in 2018. A Spirit of the Sun also received the Grand Prize in the Manga Division at the 10th Japan Media Arts Festival in 2006. Known for tackling themes that resonate with adult readers, his series have often crossed over into mainstream public consciousness, with some, like The Silent Service, reportedly being read by members of the National Diet of Japan. His consistent output of high-stakes, thought-provoking dramas has established him as a defining voice in the seinen manga genre, influencing how comics can address serious contemporary and historical issues.