Jean-Pierre Bel was born in a communist family, his father was business executive, his mother was employed. The daughter of Robert Naudi, Chairman of the General Council of the Ariège, was the first wife of Bel. They married in 1985. He has two daughters from this marriage, Julie and Mary. Since 2001 Bel is divorced.
In the years 1960-1970, Jean-Pierre Bel was firstly involved in the activity of solidarity networks in the south of France, supporting the Spanish movements fighting against Franco's dictatorship.
He was twice elected to the Senate: in September 1998 and ten years later, in September 2008. Bel acted as a President of the Socialist Group in the Senate from 2004 to 2011. Following the September 2008 Senate election, Bel represented the Group, gambling for the post of President of the Senate on 1 October 2008, but because the right held a majority of seats in the Senate, he was defeated by Gerard Larcher. After the left have won a Senate majority in the September 2011 Senate election, Bel was elected as President of the Senate on 1 October 2011 with 179 votes against 134 votes for the right's candidate, outgoing Senate President.