In his post-gymnastic career, Carlberg formed his own Gymniska Förbundet in 1928. Publishing the magazine Gymn, the society underlined what it saw as the decadence of Western society, drawing heavily from Elof Eriksson. This group fizzled out by 1932 although Carlberg was a founder and the main financial supporter of the anti-Semitic Manhem Association, a study group which he helped set up in 1934. The group's membership was cross party, involving members of the Nationalsocialistiska Arbetarpartiet, Per Engdahl's Riksförbundet Det nya Sverige and the Riksförbundet Sverige-Tyskland, amongst others.
A strong supporter of Nazism, Carlberg recruited men for both military and civilian service for the Third Reich during World War II. By this time he had become a very rich man due to his business interests and used his money to disseminate Nazi propaganda and to fund the Svensk Opposition of Per Engdahl.
Following the war, his Hjälpkommittén för Tysklands barn worked as a relief organisation for German officers, whilst his Svea Rike publishing house, originally set up in the 1930s, was turned over to Neo-Nazism. He also became the largest shareholder in Nation Europa, and set up a Carlberg Foundation aimed at youth. In 1958, Carlberg was fined 15,000 Krona for spreading antisemitic propaganda by Carl-Gustaf Herlitz.[2]
After his death in Stockholm he left his apartment to the Foundation and in 1965 it was raided by police due to a tip-off that the groups using it had stashed weapons there.
