Arnmundur graduated from the Icelandic Academy of the Arts in 2013. His film credits include A WHITE, WHITE DAY, THE QUIET STORM and ELEVEN MEN OUT. His TV roles include Sonur Oddu in WORLD'S END, Ulfur in THE CLIFF, National Geographic's GENIUS PICASSO, Stefan in Series 2 of TRAPPED on BBC Four and Lars Bleymann in ITV's SHETLAND. In 2017, Arnmundur was nominated for the Icelandic Theatrical Awards (Gríman) for 'Best Actor in a Leading Role' and 'Singer of the Year'.
Arnmundur can next be seen in the feature films REPLY TO A LETTER FROM HELGA and ENGINE NOISE.