He was a son of Frithjof M. Plahte (1836–1899) and Marie, née Birch (1852–1937).
He was a brother of Herbert and Erik Plahte, and an uncle of Frithjof M. Plahte Jr. and Hans Barthold Andresen Butenschøn Jr. His father had settled at Høvik in Bærum and Viktor lived there.
[1][2][3] He was, however, born in Surrey and took practical business training in England as well as in Sweden.
[7] He chaired the Norwegian Bankers' Association from 1919 to 1921, as well as Christiania Portland Cementfabrik.
[10] There is a road in Bærum named Viktor Plahtes vei.