Ernest John Harrison was a journalist, author, and judoka. He wrote many books about the practice of judo, some of which were among the first books in English on the practice.
Harrison began his career as a journalist, working for newspapers in England, British Columbia, and Japan. He enjoyed wrestling, and while working for the Japan Herald in Yokohama, he began training in jujutsu. He later moved to Tokyo, and in 1911, he became the first foreign-born person to achieve shodan (black belt ranking).
In World War I, Harrison served in the Labour Corps of the British Army, and later transferred to Military Intelligence. Following the war, he became the official press attaché and ELTA correspondent in the Lithuanian legation to the U.K. in London. He published several books about Lithuania. During the Second World War, Harrison worked as censor in the British Post Office. After the war, he wrote and translated judo books.