Sigurgeir was born on August 3, 1890, in Eyrarbakki, Iceland.
He was educated in Reykjavík in 1913[clarification needed] and graduated in theology from the University of Iceland in February 1917.
From 1917 till 1918 he served as assistant to the Reverend Magnús Jónsson in Ísafjörður and was ordained priest on 7 October[clarification needed] in Reykjavík Cathedral by Bishop Jón Helgason.
In the winter of 1937 and 1938 he travelled to London, Cambridge and Oxford.
He travelled extensively and represented Iceland at numerous meetings and assemblies around the world.