At age of 19 he started part-time job writing naval articles for the New York Herald and later was sent as foreign correspondent to London.

In 1915, he was sent back to America to investigate suspicious activity on New York's docks and apocryphally averted an attempted German bombing.

[citation needed] In his 1921 book Sea-power in the Pacific : a study of the American-Japanese naval problem, he predicted naval conflict between Imperial Japan and the United States and expanded the topic further in 1925 book The Great Pacific War.

[citation needed] Contrary to popular belief, neither book predicted an aerial attack on Pearl Harbor.

Instead, he predicted that the aerial attack would occur in US-colonized Philippines, then having the largest concentration of US naval vessels in the Pacific.