[5] According to the biographical dictionary Svenska män och kvinnor, he was considered to have been one of the most acclaimed writers and speakers in the country until 1941, when he became a leading promoter of Nazi propaganda in Sweden.

An attempt was made in 1932 to incorporate his group into the newly formed Nationalsocialistiska folkpartiet of Sven Olov Lindholm (a pro-Nazi party) although Engdahl resisted their overtures.

It placed an emphasis on racial nationalism, advocated the Madagascar Plan, and called for the replacement of the existing Swedish parliament with a corporatist body elected on an occupational franchise.

[11] The group advocated Swedish entry into World War II on the Axis side and went public with this aim in 1942,[12] but in fact the country stayed neutral.

After World War II, Engdahl revived Nysvenska Rörelsen, publishing a paper, Vägen Framåt ('The Way Forward'), that concerned itself with attacks on communism and capitalism.

[15] His book Västerlandets Förnyelse, published the same year, was widely read in such circles and was adopted as the chief ideological document of the ESM in 1954.

[7] He also served as part of the journal's five man editorial board alongside Hans Oehler, Paul van Tienen, Erik Laerum and Erich Kern.

[20] His name once again became controversial after his death, when, on 21 October 1994, the newspaper Expressen published a story about information they found in his archived personal correspondence, revealing that Ingvar Kamprad, the founder of IKEA, had been a member of Engdahl's groups during the war.

[20][21] Kamprad publicly acknowledged his youthful fascist involvement, called it "delusional", and had an IKEA employee search through Engdahl's archives to find other preserved correspondence between the two.

[23] According to Åsbrink, Kamprad said to her in a 2010 interview that "Per Engdahl is a great man, and I will maintain that as long as I live" (Swedish: Per Engdahl är en stor människa, och det kommer jag att vidmakthålla så länge jag lever), although a spokesperson for Kamprad stated that he rejected fascist and Nazi-sympathizing ideas.