He then worked as a teacher before commencing music studies under Guðmundur Jónsson at the Reykjavik Academy of Singing.
Later, he studied at the Hochschule für Musik und darstellende Kunst in Vienna, Austria, under Helene Karusso, Christian Möller and Wolfgang Gabriel.
Other recordings include a set of opera arias with the Iceland Symphony Orchestra and Arnold Östman, and Schubert's Schwanengesang and Winterreise with pianist Jónas Ingimundarson.
Sigmundsson is featured on the Pentatone of Corigliano's opera The Ghost of Versailles, taken from live performances in 2015.
[2] Sigmundsson is a visiting professor at the Listaháskólai Islands (Iceland University of the Arts).