[1][2] After studying his secondary and Spanish Baccalaureate education in Alcorcón, he graduated in information science from the journalism branch of the Complutense University of Madrid.

[4] In 1997, he was named deputy editor of Informativos Telecinco, a position he held for eleven years, where he was responsible for the process of digitalising newsgathering, the first time this was used in Spain.

In January 1998 the channel gave him the presenting role on La mirada crítica, the daily daytime current affairs discussion show, every Friday.

[22] In June 2023, it was reported that Mediaset España had offered him a contract worth over €1 million to jump ship back to their network, but he had rejected it, saying that Telecinco had neglected its news broadcasts, and he would have to start over to resuscitate their coverage.

[4] In 2022, he published the political thriller Operación Kazan, a novel about a complex spy plot in which the KGB, CIA and National Intelligence Centre are all involved.

They are both supporters of Atlético Madrid, with Vallés quipping in 2023 that he was "more worried about whether Atleti would sign a striker than the formation of the government", after the protracted negotiations to agree a ruling coalition after that year's general election.