He was the son of the artist Annie Caroline Pontifex "Charley" Toorop and the philosopher Henk Fernhout.
His parents had a bad marriage, and by constant financial problems, the family could not afford a permanent residence.
In 1937, the Hague Gallery Nieuwenhuizen Segaar organized a special exhibition about the three generations Toorop family.
He taught alternative art education 'Ateliers' 63' in Haarlem, and among his students were Jan Dibbets, Wessel Couzijn, Carel Visser, Constant and Armando.
In 1928, Fernhout interrupted his studies, and spent the last year of high school in Paris with his mother.
The reason for this stay was twofold: Rachel's weak health required a warm climate, and Fernhout wanted to study Renaissance painting.
Fernhout fell into depression during this period, which not only coincided with his broken marriage and the German occupation, but also with doubts about his artistry.
The famous French painter of the Ecole de Paris, Jean Bazaine had a lot of influence on the painting of Fernhout.