Ogmund was a nobleman of Sodor, born in Iceland in 1045 to Sigurd of Cronk and his wife Helga. They later returned to Sodor with the infant Godred Crovan, later to be king of Sodor, and his mother, Gerda. He and Crovan were best friends, and, after Helga's death, step-brothers, for Sigurd remarried to Gerda. By the time of Sigurd's death in 1063, Ogmund was virtually the most powerful man on Sodor.
Crovan later left Sodor to conquer his father's former lands. He completed his goal in the battle of Sky Hill in 1079, which Ogmund was sadly killed in. The Ogmund saga was written in his honour, and sung at his funeral. The surviving copies of the saga also describe events that happened after his death, such as the Norman invasions of Sodor in 1089 and 1094. Ogmund was survived by his son, Olaf.