His mother, descended from indigenous princes of the Volga Finns of Meshchera and Mordovia, died two days after his birth, whilst Elim's paternal grandmother was the Finnish beauty and philanthropist Aurora Karamzin.

He had six half-brothers and half-sisters from his father's second marriage with Princess Elena (Hélène) Petrovna Trubetskaya.

Speculating in 1895 about the richest man on earth, The Atlanta Journal-Constitution stated that "the wealth of Elim Demidoff is beyond calculation".

[1] In the early 20th century, Emperor Nicholas II sent prince Elim as the Russian ambassador to the Greek court.

His Greek connections played a role when he arranged his nephew Prince Paul of Yugoslavia to marry Princess Olga of Greece and Denmark in 1923.