He was a son of vicar Niels Anton Aall (1833–1896) and his wife Mathilde Susanne Dahl (1842–1910).
His grandfather, Hans Cato Aall (1807-1862), was a Member of Parliament and mayor of Hammerfest.
His sister Marna Aall (1873–1948) was married to philosopher Kristian Birch-Reichenwald Aars from 1895 to 1910.
[3][4][5] Aall's family moved a lot during his early years, since his father was a parish priest.
He published several works, including the 1903 thesis Über die Wirkung der Wiederholung eines Elementes bei gleichzeitiger Vorführung mehrerer Schriftzeichen.