Ainey was a delegate to the International Parliamentary Union for International Peace held at Geneva, Switzerland, in 1912, and at The Hague in 1913. He served as secretary and president of the Japanese-American group of inter-parliamentarians and delegate in 1914 to Tokyo, Japan, and to Stockholm, Sweden. He resumed the practice of law in Montrose.
Ainey was involved in international diplomacy, serving as a delegate for the International Parliamentary Union for International Peace, participating in conferences in Geneva and The Hague, and representing the Japanese-American group of inter-parliamentarians. He later resumed his legal practice in Montrose after these diplomatic endeavors.