A year later, he enrolled at the Norwegian National Academy of Fine Arts of Oslo, where his main teachers were August Eiebakke and Olaf Willums from 1929.
His pictures are heavily influenced by rural life and traditional Norwegian folk art.
Fjell's early paintings are dominated by dark and earthy hues and often has grotesque motifs.
Throughout his long career, the female figure and various fertility-symbols are recurring motifs in Fjell's pictures.
Fjell's main work consists of Kalven reiser seg, Violinen and Likkjøreren on display at the Nasjonalmuseet.