[1] He served as Chief of the Defence Staff (JEMAD) of the Spanish Armed Forces during the first government of prime minister José Luis Rodríguez Zapatero (2004–2008).

He was promoted to brigadier general in 1998[6] and he was appointed to the office of Deputy Director-General for Plans and International Relations in the Directorate-General for Defense Policy (DIGENPOL) of the Ministry of Defence.

In April, the newspaper El Mundo published information that assured, according to CNI sources, that Saiz had repeatedly used resources and public funds of the centre for personal use and enjoyment during his professional trips abroad.

"[14] At the same time, the CNI ordered the withdrawal of three field agents at the request of the Cuban government, something that was seen by the members of the agency as a sign of weakness.

[17] Sanz Roldán dedicated his first years as head of the agency to "pacify", due to the bad situation that the previous director had provoked between the agents and the governing bodies.

[28] According to Sanz Roldán on September 29, 2018, the following day to the referendum, when he arrived to the CNI headquarters, there was many "long faces" and the "feeling" that the centre "could have done better".

However, Sanz Roldán defended the work of the CNI and assured that he asked the government directly if the intelligence that the center had provided to the executive "had been useful to them," and the answer, he said, was "yes".

In early 2019, José Manuel Villarejo sent a letter to the Prime Minister accusing Sanz Roldan of threatening certain judges of the National Court with data of their privacy so that they stop investigating issues that affect the CNI.

Due to this situation, Paz Esteban López, who was the Secretary-General of the CNI and, therefore, the agency's second authority, assumed the direction ad interim of the intelligence service, being the first woman to hold the post.

[31] After leaving the CNI direction, Sanz Roldán was appointed Chairman of the Social Council of the University of Castilla–La Mancha in November 2019.