He is a descendant of 19th Century military hero, General Manuel Diez Canseco y Corbacho, and is related to President Fernando Belaúnde Terry.

His father, a banker, was general manager of the Banco Popular del Perú, which afforded the family a high level of material comfort.

[3] During his time at university he became a member of the left-wing party Vanguardia Revolucionaria, and soon moved out of Lima to work with mine workers in the central highlands.

Later, when Vanguardia Revolucionaria merged with other groups to form the Partido Unificado Mariateguista, Diez Canseco emerged as a leader in the new party.

In December 1996, he was one those taken captive by Túpac Amaru Revolutionary Movement (MRTA) guerrillas in the Japanese embassy hostage crisis in Lima, but was released after several days.

[3] During his time at university he became a member of the left-wing party Vanguardia Revolucionaria, and soon moved out of Lima to work with mine workers in the central highlands.

Later, when Vanguardia Revolucionaria merged with other groups to form the Partido Unificado Mariateguista, Diez Canseco emerged as a leader in the new party.

He was critical of what he saw as the caudillismo of American Popular Revolutionary Alliance (APRA), and during the 1990s, was a vigorous opponent of the dictatorship of President Alberto Fujimori.

[11][12] However, said measure was annulled on 4 April by the Fifth Constitutional Court of Lima, in response to an amparo action filed by the legislator, since the sanction affected due process, the right to defense and honor of the congressman.

In 1988, he was again suspended on 3 September for having punched a fellow congressman in the mouth, and for having violated congressional norms by speaking by telephone with a television news program during a closed session of the legislature.

[17] In March 1997, Diez Canseco's car was fired upon by heavily armed assailants wearing bullet-proof vests, but he was not riding in it at the time.

The attackers took control of the vehicle, and took its occupants, Diez Canseco's chauffeur, bodyguards, and a friend, to an unknown location in Lima where they were interrogated and later freed.

In a posthumous statement on the following day, the congressman's family asked that those congressmen who voted in favor of the 90-day sanction against him not attend the wake, tribute and burial of the renowned politician.