Born in Pisa, Biondi was Secretary of the Italian Liberal Party (PLI) from 1985 to 1986, and later its president. He was a member of the Italian Chamber of Deputies from June 1968 to May 1972, and then from June 1983 to April 2006. He was a Senator from April 2006 to April 2008.
In 1993, together with the last PLI leader, Raffaele Costa, Biondi founded the Union of the Centre, a small faction of the new Forza Italia (FI) party. He served as Minister of Justice for a period of eight months (having previously served also as Ecology Minister in the 1980s).[3] Biondi was appointed President of Forza Italia's National Council in 2004.[3]
Following the dissolution of Forza Italia in 2009, Biondi remained in its successor organisation, the People of Freedom (PdL), for a further two years before leaving to join the refounded Italian Liberal Party. In 2014, Biondi was among a group of disaffected members who broke from that party to form The Liberals (I Liberali).[citation needed]