Rui Fernandes was born in Lanhelas, Caminha. He began his musical studies at the age of eight in the Banda Musical Lanhelense. He later studied with José Borges at the Escola Profissional de Música de Viana do Castelo. At 18, he continued his studies at the Escola Superior de Música de Lisboa with Ismael Santos and, at 23, he joined the Royal Northern College of Music in Manchester, where he studied with Chris Houlding. Throughout his education, he also attended courses with the most prestigious trombonists worldwide, such as Josep Alessi, Ian Bousfield, Don Lucas, Gusztav Hona and David Bruchez, amongst others.

Rui Fernandes has played with several chamber music groups and performed solo with the Orquestra de Câmara de Cascais e Oeiras at the Estoril Music Festival. He has also played with the principal Portuguese orchestras, including the Orquestra Sinfónica do Porto, the Orquestra Sinfónica Portuguesa and the Orquestra Metropolitana de Lisboa, playing with prestigious conductors and soloists. As a teacher, he has taught trombone at the Alhandra and Minde Music Schools. From 2008 to 2010, he was trombonist with the Remix Ensemble Casa da Música. He has been 2nd trombone soloist of the Gulbenkian Orchestra since 2010. He is also currently a member of the trombone and tuba group, Wild Bones Gang.