Born in London in 1889. Spent much of his early life involved with brushes with the law. Was sent to reform school and was sent to live with relatives in Canada after his release.

Work in various jobs but exhibited an immense talent as a gambler. After accumulating vast earnings from his talents his was able to associated with members of high society. At one such affair was introduced to Chinese revolutionary Sun Yet-sen. Yet-sen was leading a revolt against the Manchu dynasty, trying to supplant it with a unified China, complete with western-based democracy. Yet-sen had brokered deals which provided him with sufficient funds to lead the revolution but was having trouble securing arms for fighting.

Cohen suggested that he could fully arm the revolutionaries and was engaged to do so. His success in doing so prompted Yet-sen to bring Cohen in as a trusted advisor after the revolution’s success in 1912. Cohen accepted the invitation and after the end of World War I, traveled to China and was named the Head of Intelligence for Yet-sen in 1922.

Established an elaborate counter-espionage system, reporting to Yet-sen events and activities within China as well as Japan. Employed two spies, Isaac Lincoln and Lionel Philip Kenneth Crabb, both of whom were known for the adventurous exploits.

Often engaged in hand to hand combat in beating down insurrection movements against Yet-sen. At all times wore a gun in his shoulder holster and one in a hip holster (thus earning the nickname “Two-Gun) and often led the charge into enemy lines. Devised methods of intelligence gathering, establishing sophisticated networks involving common farmers in various provinces of China as well as foreign diplomats and businessmen. Also, employed various levels of interrogation to extract information from captured enemies, including torture and execution.

After Yet-sun’s death in 1925, Cohen assumed the same role with Chiang Kai-shek, Yet-sun’s successor. Worked vigorously to gather information about the Chinese Communist Party which was gaining a foothold in China. Likewise, obtained information from people close to Japanese military intelligence. Learned that Japanese military intelligence officer Major Ryukichi Tanaka and his mistress Eastern Jewel planned to create a violent disturbance in Shanghai in order to provide Japan with an excuse to attack and invade the city. Warned Kai-shek, but was taken prisoner by the Japanese which in Hong Kong.

Was released by the Japanese after the end of World War II. Upon his return, found that he had been replaced in his position and left China. Eventually returned to Canada where he died in 1970.