He worked briefly within the Communist Party of Norway, but later shifted to the far right and joined Fatherland League.
He was released from Opstad tvangsarbeidshus in 1933, and despite taking the examen artium in 1934 he spent most of his future career as an activist.
Historian Terje Emberland has analyzed his views as loosely based on Norse mythology, with millennialistic and messianistic aspects.
[1] He became known for pasting activistic posters in the streets of Oslo, particularly in December 1938, when his actions were probably inspired by the Kristallnacht.
[1] Langfeldt (and Ørnulv Ødegård) would later, famously, apply the same diagnosis to the Nobel Prize in Literature recipient Knut Hamsun.
He managed to write with a fair amount of suspense, but the book lacked in fantasy and logic.
During the occupation of Norway by Nazi Germany, which lasted from 1940 to 1945, Amble was recruited as an agent for Abwehr.