At the outbreak of World War I, Hunter enlisted as an officer in the United States Army Medical Corps.

[7] In September 1921, Hunter won the state amateur championship tournament for the second time against C. H. Walter of Oakland.

In May, he played for an American team in an international match that was held at Royal Liverpool before the start of the Amateur Championship the following week.

[11] The following month, Hunter played in the Open Championship held June 23–25 at the Old Course in St Andrews, Scotland.

[1][4] In the 1909 amateur golf championship of Southern California, Hunter, age 19, won the title against N. F. Wilshire.