He was born in Furnes as the son of banker Christian Fredrik Stoud Platou (1824–1883) and Elise Sem (1833–1923).
After her death he married French citizen Alexandra Henriette Maud de Ciccolini in April 1926 in Nice.
[1] He took commerce school in his hometown Hamar, and at the age of 16 he became a brewer's apprentice at Christiania Bryggeri in Norway's capital.
[1] He was behind the founding of the brewery, when he bought Det Sembske Bryggeri and asked in Bergen's local press for further investments.
[6] Platou was decorated as a Knight, First Class of the Royal Norwegian Order of St. Olav in 1910.