It dates to the 1930s under Roosevelt and became common again in the 1970s and has remained fairly common since then:
https://en.wikipedia.org/wiki/Czar_(political_term)#Modern_u...
https://en.wikipedia.org/wiki/List_of_U.S._executive_branch_...
https://en.wikipedia.org/wiki/Czar_(political_term)#Modern_u...
https://en.wikipedia.org/wiki/List_of_U.S._executive_branch_...