Fernández Aguirre was born in Barakaldo (Biscay). A disciple of Félix Lavilla, he specialises in accompanying singers in Vienna and Munich and has Wolfram Rieger as his mentor.
He is a regular pianist for singers such as Carlos Álvarez, Lisette Oropesa, Ismael Jordi, Sabina Puértolas, Javier Camarena, Carmen Solís, David Alegret, Marina Monzó, Jose Antonio López, Serena Sáenz, Airam Hernández, Ruth Iniesta, Joan Martín-Royo, Vanessa Goikoetxea, Nancy Fabiola Herrera, Miren Urbieta, Núria Rial, Berna Perles etc... Fernández Aguirre also does recitals with Ermonela Jaho, Carlos Chausson, Mariella Devia, José Bros, Measha Brüggergosman, Andreas Schager, Martina Serafin, Celso Albelo, Cristina Gallardo-Domâs, Simón Orfila, Sylvia Schwarz, Chistopher Robertson, Ainhoa Arteta, Martin Nusspaumer, María Bayo, Borja Quiza, María José Montiel, José Luis Sola, Maite Beaumont, David Menéndez, Isabel Rey, Gabriel Bermúdez, Virginia Tola, José Sempere, Ángeles Blancas, Pancho Corujo and Leontina Vaduva, among many others. He performs at most Spanish and international theatres and festivals, such as the Staatsoper and the Musikverein in Vienna, the ROF in Pesaro, the Bregenz Festival, the Tchaikovsky Hall in Moscow, the Smetana Hall in Prague, the Carnegie Hall in New York, the Teatro Solís in Montevideo, the Usina del Arte in Buenos Aires, in Guadalajara, Álamos Sonora, in Dubai, Damascus, Algiers...
He has likewise accompanied courses and expert classes by Teresa Berganza, R. Scotto, J. Aragall, I. Cotrubas, R. Vargas and Frederica von Stade. He has acted as the official pianist of Operalia (presided over by Plácido Domingo) and as a judge at the International Singing Competitions of Bilbao, Logroño, and Bogotá.
A defender of Musical Heritage, he has helped to recover the five operas for small venues by Sevillian composer Manuel García. Fernández Aguirre's list of albums includes Granados Songs Integral, Carlos Álvarez Live in La Monnaie, Canciones en la Alhambra (Songs in the Alhambra), Ametsetan, Carneriana, La Seduzione, (Ibs), a complete collection of songs by Antón García Abril, and Ensueños (Dreams) with AIM Records.
An Honorary Patron of the Victoria de los Ángeles Foundation, in 2010 he received the Ópera Actual award ‘for his dedication to classical singing and the growing prestige he is achieving in his field’.