He is remembered now as an envoy who tried to negotiate peace and understanding with the United States while the Japanese government under Emperor Shōwa was secretly preparing the attack on Pearl Harbor.

Early foreign service experience included posts in Chile, Italy, Germany, and Peru.

On September 27, 1940, Kurusu signed the Tripartite Pact in Berlin on behalf of the Japanese Empire, entering into a 10-year military and economic treaty between Germany, Italy, and Japan.

[10] After peace talks between the United States and Japan bogged down in 1941, Kurusu was dispatched as the Imperial government's "special envoy.

"[12] Two days later, Secretary of State Cordell Hull brought Kurusu to the White House to meet with President Roosevelt.

On November 20, Kurusu presented Japan's proposal that the United States cease aid to China and resume trade relations that had been frozen in December 1939.

"[14] Over the next three weeks, Kurusu and Ambassador Kichisaburō Nomura continued to confer with Hull while awaiting Japan's reply.

"[16] In addressing Congress the next day, President Roosevelt said, "Indeed, one hour after Japanese squadrons had commenced bombing in Oahu, the Japanese ambassador to the United States and his colleague delivered to the Secretary of State a formal reply to a recent American message.

[19] Kurusu was a visiting professor at Tokyo University and lived at a country estate in Karuizawa with his wife, Alice.