He was a close associate and friend of Sun Yat-Sen, and was active in the struggle to liberate China from the Qing dynasty.

[3][4] Claudio learned to write in fluent Chinese, and contributed multiple articles later on for the Chinese-language newspaper The Fookien Times Yearbook from 1966 to 1968.

with the only summa cum laude in the school as part of the second batch in 1940 at the Ateneo de Manila.

[7] He was known as the court's "activist" justice because of his dissenting opinions in many vital cases affecting the Marcos administration.

He was the lone dissenter in many cases, such as the High Tribunal's decision upholding the constitutionality of the Judiciary Reorganization Act of 1980.

[5][9] After his retirement, he was appointed as the Philippine Ambassador to the United Nations, where he died of cancer in Manhattan, New York on November 27, 1989, at the age of 71.