Important aspects of Fagerlund’s work are his interest in large-scale forms and a profound view of music expressing fundamental questions and existential experiences. Fagerlund was described in BBC Music Magazine as displaying 'boundless technical resource at the service of a considerable imagination.' A highly virtuosic instrumental feel and strong sense of musicianship is noticeable in all of his works, creating musical dramas in which powerful expression is combined with intensity and vivid communication, as well as an openness towards different musical traditions.
Works by Fagerlund have been commissioned and performed by numerous major orchestras, outstanding conductors and musicians all over the world. His output spans opera to chamber and solo works, the most significant pieces being his concertos and works for orchestra. Performers of his works include the BBC Symphony Orchestra (Sakari Oramo), Bergen Philhamonic Orchestra (Edward Gardner), Finnish Radio Symphony Orchestra (Hannu Lintu), Singapore Symphony Orchestra (Osmo Vänskä), Buffalo Symphony Orchestra (JoAnn Falletta), Pekka Kuusisto (violin), Hervé Joulain (horn), Bram van Sambeek (bassoon), and Christoffer Sundqvist (clarinet).
In 2011 Fagerlund was awarded Finland's renowned Teosto Prize for his orchestral work Ignite. The same year Ignite was also selected as a recommended work at the International Rostrum of Composers 2011 in Vienna.
Since 2013 Fagerlund has been artistic director of the RUSK Chamber Music Festival in Jakobstad, Finland.