 Olaf Holtedahl was born in Kristiania (modern-day Oslo), Norway, the son of Arne H. Holtedahl, superintendent of pauper administration, and his wife, Mathilde Madsen.Around 1903 he did his obligatory military service at Gardermoen, just north of Oslo, and here met Captain Gunnar Isachsen who greatly influenced him, and first inspired his interest in polar regions.In 1909, Isachsen invited Holtedahl to join him in explorations of Spitsbergen as official geologist of the group.