[1] During the 1941–1944 Nazi German occupation of Estonia, he has been accused of being a collaborator with Germany during his service in the police force of Estonian Self-Administration [citation needed] and of committing war crimes against Jews.
At a young age, he started playing sports, including football, basketball and ice hockey.
[6] In 2001, the Simon Wiesenthal Center published allegations that Mikson committed war crimes against the local Jews during the German occupation of Estonia, when he was working as Deputy Head of Police in Tallinn/Harjumaa.
[7] Mikson's descendants have reportedly claimed that he had been at least on one occasion imprisoned by the Germans for hiding details about witnesses from his superiors.
[7][failed verification] Mikson had three children with his wife Sigríður Bjarnadóttir, including footballers Jóhannes Eðvaldsson, who played for Celtic F.C.