He entered public service in the office of the Commonwealth Attorney General of Puerto Rico, first as an assistant from 1947 to 1952, then as acting Attorney General from 1952 to 1953, then as a deputy from 1953 to 1956, and finally as the Secretary of Justice of Puerto Rico from 1957 to 1958.
[1] In 1966, the United States Congress passed an act reorganizing the United States District Court for the District of Puerto Rico as an Article III court, with the judges thereof having life tenure and salary protection.
Fernandez-Badillo was nominated by President Lyndon B. Johnson on September 18, 1967, to the United States District Court for the District of Puerto Rico, to a new seat authorized by 80 Stat.
He was confirmed by the United States Senate on October 12, 1967, and received his commission the same day.
He assumed senior status due to a certified disability on June 30, 1972.