Guinaldo, after passing through several media outlets such as La Sexta or Telemadrid, among others, today holds the position of intern at Agencia Sinc. A news agency dedicated to science and where he assures that “I am very comfortable now where I am , I think we can write very honest things. We don't need to write flashy headlines or use clickbait to get people's attention." An agency in which, according to Guinaldo himself, "they do very, very rigorous journalism, the most in Spain."

The now scholarship holder for the Sinc Agency, decided to study journalism "for reasons for which I do not feel identified at all now." “I loved listening to the radio more than on TV, I watched all the league games and commented on them with my friends. That was the main reason for getting into the race, then as I was studying it, my chip was changing quite a bit”. Guinaldo in turn confesses that “all the men wanted to do sports journalism. Between class and class, it seemed like “El Chiringuito”. I was disenchanted with that area”.

For reasons like this, Sergio Guinaldo became interested in other branches and studied a Master's degree in Journalism and Science Communication. Guinaldo comments that there are professors who left their mark on him and that "based on this type of teaching, my mind opened up more and I became more interested in the subject of politics, society... but among all this, what interested me the most was the environment". That is why “once I finished my degree I did not know anything about the environment and I felt the need to complete the information on this branch”.

Sergio Guinaldo shares his vision on journalism. He declares that “I think what I like the most is feeling that I am doing useful work for society”. Although he also comments that in other media where he has been, “it is very difficult to do the hours that you have stipulated. You always do more hours than you have in the contract.” On the other hand, Guinaldo sends a message of optimism stating that "it's a bit frustrating but in the end it pushes you to continue so that one day you can stabilize yourself and end up in a place where you can be comfortable."