Harald was born in Ringerike, Norway in 1015to Åsta Gudbrandsdatter and her second husband Sigurd Syr. Sigurd was a petty king of Ringerike, and among the strongest and wealthiest chieftains in the Uplands. Through his mother Åsta, Harald was the youngest of King Olaf II of Norway / Olaf Haraldsson's (later Saint Olaf) three half-brothers. In his youth, Harald displayed traits of a typical rebel with big ambitions, and admired Olaf as his role model. He thus differed from his two older brothers, who were more similar to their father, down-to-earth and mostly concerned with maintaining the farm.