He was a member of the United States Army and held the rank of Sergeant Major. At some point, he met and married Mrs. Ishii and consummated their relationship which led to their alignment in work and the creation of their beautiful daughter O-Ren.
When O-Ren was only nine years old, Mr. Ishii and his wife were murdered by Matsumoto and his men, who managed to break into their house during the night. Although he was outnumbered by the kumi-in, Mr. Ishii refused to accept his fate like a coward. His training in the military was not in vain, for it became apparent that he was an extremely skilled martial artist. He managed to disarm and ruthlessly kill two of the armed assassins before falling to a fatal katana-inflicted wound to his heart by the hands of Riki.
After falling to the ground, he, before receiving the final blow, whispered something unintelligible to O-Ren, who was hiding under her parents' bed in their bedroom where the fighting occurred.
Immediately after Mr. Ishii's moment of death, Mrs. Ishii was executed by Matsumoto himself.