Prior to joining government, Mr. Drilon specialized in labor and employment issues.
He first joined government as Deputy Minister of the Ministry of Labor and Employment in 1986. He then served as Secretary of the Department of Labor and Employment from 1987 to 1990, Secretary of the Department of Justice from 1990 to 1991 and 1992 to 1995, and Executive Secretary from 1991 to 1992.
He was elected as Senator from 1995 to 2007, 2010 to 2013, and 2016 up to present. He served as Senate President for the 10th, 11th, 12th, and 13th Congress, and is the current Senate Minority Floor Leader.
Mr. Drilon ranked third among the successful examinees of the 1969 Bar Examinations. He was admitted to the Philippine Bar in 1970 and is a member of the Integrated Bar of the Philippines.