Cirilo Fernández is a pianist, composer, and music producer born in Switzerland and raised in Buenos Aires, Argentina. Creator and producer of Fernández 4, he has developed an extensive career both at the helm of his own projects and collaborating with other artists. For five years he was a regular pianist with the Boris Big Band and the Ensamble Realbook Argentina, was a member of the Mariano Sívori Sexteto and the Sorin Octeto, and was the bassist for the bands Elbou and Octafonic. With the latter, he performed at festivals such as Cosquín Rock and Pepsi Music, in addition to opening for Faith No More at Luna Park and Jacob Collier at the Vorterix Theater.

As a producer, he has worked with artists such as Ca7riel, Emmanuel Horvilleur, Julieta Venegas, Julieta Rada, Julián Kartún, Rosario Ortega, Miguel Bosé, and Ana Torroja, among many others. He has also shared stages and recordings with musicians such as Hermeto Pascoal, Kendrick Scott, Walter Smith III, Robin Eubanks, Jaleel Shaw, and Juan Cruz de Urquiza. His work encompasses composition, arrangements, performance, and music production, including projects for film and other audiovisual productions.

In 2017, he received the Gardel Award for Best Jazz Album for "Mute", by Fernández 4, released by Club del Disco. His next work with the group, "Retrovertigo" (2019), received three nominations at the 2020 Gardel Awards, including Producer of the Year and Best Jazz Album. His discography also includes "No Fear" (2014), "IKE" (2021), and various recordings with Octafonic and other ensembles. In 2023, he returned to the piano trio format alongside Mariano Sívori and Daniel "Pipi" Piazzolla to release "Cabezón", continuing a collaboration that had begun with the 2009 release of "Triathlon".