His brother was the ore caster and director of the Munich Academy of Fine Arts Baron Ferdinand von Miller.

With the elevation of his father Ferdinand into the Bavarian nobility on 12 October 1875 and with the inscription of the family name on the roll of the aristocracy of the Kingdom of Bavaria on 30 December 1875, Oskar was simultaneously ennobled.

At this exhibition, on 16 September 1882, in partnership with Marcel Deprez, he succeeded in transmitting an electric current for the first time over a distance of approximately 60 kilometers, from Miesbach to the Glaspalast in Munich.

[1] For several decades Miller worked on the project known as Bayernwerk, which had to use the power of Bavaria with an installed capacity of 1253 million kilowatts of the land electrics supply.

Famous scientists and entrepreneurs such as Max Planck, Hugo Junkers, Wilhelm Conrad Roentgen and Emil Rathenau advised him on the structure of the departments.