[1] He is the winningest coach in Icelandic basketball history for both genders, both in terms of national championships and career wins.
[4][5] In October 2016, Sigurður was forced to step down as head coach of Keflavík in the Úrvalsdeild karla due to health reasons.
[6][7][8] In January 2025, he resumed his coaching career and took over Keflavík women's team once again, replacing Friðrik Ingi Rúnarsson who resigned in December.
[9] In February 2025, he also took over the men's team until the rest of the season, replacing Pétur Ingvarsson.
[10][11] Sigurður is the younger brother of Valur Ingimundarson, the highest scoring player in the Icelandic Úrvalsdeild history,[12][8] and the uncle of basketball player Valur Orri Valsson.