He joined the youth academy of Icelandic side Stjarnan at the age of eight.
[2] When he got the chance against Bærum in the 1994 cup, he left the field injured after about 30 minutes.
Sigmundsson started his managerial career with Icelandic side HK.
[5] In 2014, he was appointed manager of Icelandic side Stjarnan.
[6] In 2021, he was appointed manager of Icelandic side Fylkir.