David D'Arcy Alexander Greig was born in Scotland on the 1st of February 1900. He was given a private education, first at Weston House School, Elgin and then at Elgin Academy. The 1911 Census of England and Wales, shows that in 1911, he was a boarder at Shrewsbury House.

David joined the new RAF in 1918 and saw service with No. 83 Squadron in France in the last year of the war. On the 13th of September, the FE 2B biplane he was flying was shot down behind German lines. He avoided capture and walked 13 miles through enemy territory and the German front line to reach his unit. For this achievement, he was awarded the Air Force Cross (AFC).

His feats between the wars and during World War Two will be included in the World War Two link.