Former Senator Juan Ponce Enrile received his Bachelor of Laws from the University of the Philippines, graduating Cum Laude and Salutatorian in 1953, and took his oath as a member of the Philippine bar in 1954. He ranked No. 11 among the successful bar candidates with a rating of 91.72% and scored 100% in Commercial Law. In 1955, he obtained his Master of Laws from Harvard Law School while on scholarship, with a specialization in taxation and corporate reorganization. He was a partner in Ponce Enrile Siquion Reyna Belo & Ongsiako Law Offices from 1954 to 1966. He was also a Professor of Law at the Far Eastern University College of Law from 1956 to 1964.
In January 1966, he entered public service as Undersecretary of Finance. Thereafter, he was made Chairman of the Board of Directors of the Philippine National Bank. He was also designated as concurrent Acting Commissioner of the Insurance Commission, where, during his stint, he revised many of the rules and regulations to make the insurance industry more reliable and stable. He then became Acting Commissioner of Customs until December 1968. While in the Finance Department, he was also appointed Acting Secretary of Finance and concurrent Chairman of the Monetary Board of the Central Bank of the Philippines. In December 1968, he was appointed Secretary of Justice, a position he held until February 1970. Thereafter, he was appointed as Secretary of National Defense until August 1971, when he resigned to run for the Philippine Senate. He was reappointed Secretary of National Defense in January 1972 and served in that capacity until November 1986. He was first elected to the Philippine Senate in 1987 and completed five full terms in the Philippine Senate. During his tenure as a Senator, he held the position of Senate President from 2008 to 2013. He also served in the House of Representatives as Representative of the first district of Cagayan from 1992 to 1995. In 2022, he was appointed Chief Presidential Legal Counsel.
He is affiliated with the Philippine Constitutional Association, Philippine Tax Institute, Knights of Rizal, Harvard Club of the Philippines, International Chamber of Commerce of the Philippines, Philippine Jaycees Senate and the Manila Overseas Press Club, among others.