He was the youngest elected member of the House of Representatives during the 9th Congress as well as the youngest Senator of the 12th Congress at the age of 37. He also holds an unprecedented record in the congressional election history of Batangas for winning in all precincts, barangays, and municipalities together with Lipa City in the 1995 and 1998 elections. Moreover, he garnered 98% of the votes cast in those two elections in the 4th District of Batangas.
During his three terms (from 1992 to 2001) as Member of the House of Representatives, most of his legislative measures, which were enacted into law deal with economic reforms and poverty alleviation. His legislative measures especially those related to taxation have a grave impact on inflation rates. Among which are the Social Reform and Poverty Alleviation Act; the Philippine Economic Zone Law; Amendment to the Special Economic Zone Law; the Retail Trade Liberalization Law; Regional Headquarters Law and the Comprehensive Tax Reform Law. However, he is most famous for authoring the Extended Value Added Tax Law, making him known as "The Father of EVAT" to many Filipinos.
In the previous Senate, he chaired the Committees on Ways and Means and on Trade and Industry.
He ran again for the Philippine Senate in the 2007 Elections but did not make it to the "magic twelve".