Butterworth is best known for his work on Asian-American foreign relations, particularly during the clash of the communists and nationalists in post-war China.

Following brief posts in Washington and Ottawa, he was assigned to the American Embassy in London, where he served as second secretary until 1941.

From 1946 to 1947, Mr. Butterworth served as the counselor of the U.S. Embassy in Nanking, China, where he held the rank of minister and was a political advisor to George Marshall.

On February 22, 1943, Butterworth and the other passengers and crew on Pan American's Yankee Clipper crashed into the Tagus River in Lisbon, Portugal.

On September 13, 1968, Butterworth was presented with the Department's Award for Heroism, he was cited:In recognition of your courage and cool-headed resourcefulness at the crash...Although injured, you broke free of the wreckage, swam to survivors in the water and assisted them in reaching floating debris which sustained life until a rescue boat arrived[3] Butterworth was an expert swimmer and helped other survivors despite two cracked ribs, all while keeping his briefcase full of classified documents with him.