In June 2017 Sigurgeir Agnarsson was appointed the Principal Cellist of the Iceland Symphony Orchestra, having served as its Associate Principal since 2003. He graduated from the Reykjavik College of Music in 1995 and continued his studies at the New England Conservatory of Music in Boston with David Wells and Laurence Lesser. Further studies followed at the Hochschule für Musik in Düsseldorf with Pr. Johannes Goritzki.

Sigurgeir teaches at the Reykjavik College of Music and has also taught at the Iceland Academy of the Arts. He has appeared as a soloist with ensembles such as the Iceland Symphony Orchestra, Bochumer Symphoniker and the Reykjavík Chamber Orchestra and also appears regularly as a chamber musician and recitalist in Iceland and abroad. He has recorded for the Icelandic Broadcasting Service and Naxos.

Sigurgeir is Artistic director of the Reykholt Chamber Music Festival, held each year in July and one of the founders of the Harpa International Music Academy.