He was considered the main ideologist of Tito's communist regime in former Yugoslavia. He had major influence on the Yugoslav military intelligence service, the notorious KOS. His original idea was to hire convicted criminals for the benefit of the service. Kardelj organized the assassinations of many Yugoslav political exiles in this way. In exchange for their services, criminals were given safe haven in the country, protected even from Interpol. They were free to rob banks and to carry on other business of their own all over Western Europe. Arkan, a mischievous son of an army officer, started as Kardelj's protege.
It is also known that he led Yugoslav delegations in the late 1940s to negotiate with Stalin and deal with his demands that Yugoslavia acknowledge the Soviet Union's supremacy.
Some above statements should be NPOVed'.
The coastal town of Ploče in southern Croatia had been renamed to Kardeljevo in Kardelj's honour in 1950-1954 and 1980-1990.