Senator Saguisag was born on August 14, 1939 in Mauban, Quezon.
He finished his primary at Makati Elementary School in 1951, then his secondary course at Rizal High School in 1955. He obtained his Bachelor of Arts degree in 1959 with honors and Bachelor of Laws degree in 1963 cum laude both at San Beda College. He acquired his master of laws degree full scholar at Harvard University in 1968.
Senator Saguisag worked as a checker, laborer, construction site guard and messenger from 1959 to 1962. From 1962 to 1972 he became an student researcher, then associate and eventually part time in Ledesma, Guytingco, Velasco and Saguisag. He became a member, Law Faculty (Assistant Dean 1971-1972) from 1961 to 1972. From 1972 to 1986 he practice law and a human rights lawyer. Senator Saguisag became the spokesman of candidate and president elect Cory Aquino from January 22, 1986.
He was elected senator in 1987 up to 1992. He was chairman of Senate committee on ethics and privilege and ad hoc committee on the Bataan Nuclear power plant and he was one of the two senators who attended all 415 session days from July 1987 to June 1990.
He married Dulce Maramba Quintanas with whom he has four children.