Fagerlund began his musical studies with violin lessons at the Turku Conservatory, where his teacher was Simo Vuoristo. After a year spent studying in the Netherlands, he applied for the Sibelius Academy to study composition and graduated from the class of Erkki Jokinen in 2004. He has also attended master classes with Michael Jarrell, Magnus Lindberg, Ivan Fedele and others.
His output covers a wide variety of genres, ranging from chamber opera to chamber music and works for solo instruments. The most prominent are his concertos and his works for orchestra.
Together with clarinettist Christoffer Sundqvist, Fagerlund is Artistic Director of the RUSK Chamber Music Festival they founded in Pietarsaari/Jakobstad, Finland in 2013.
Fagerlund is the Composer in Residence of The Royal Concertgebouw in Amsterdam season 2016/17.

2010 – Nominated for the Nordic Music Prize for Sky
2010 – Record of the Year Award of the Yle music editors for the recording of Döbeln
2011 – Emma Award for best classical, for the orchestral Isola
2011 – Teosto Prize for the orchestral Ignite
2011 – Ignite selected as a recommended work at the International Rostrum of Composers in Vienna
2016 – Nominated for the Nordic Council Music Prize for Mana- Concerto for Bassoon and Orchestra