What did Frank Derry do before he became a member of the Smokejumpers as noted in the nonfiction book, Young Men & Fire?

Frank Derry was a stunt man from California, who first jumped from an airplane dressed as Santa Claus, and then went on to join a flying circus act that traveled throughout the West. Derry was one of the Forest Service's nine original smokejumpers. According to the author, Derry was one of the Forest Service's best jump instructors, one of its best riggers, and made vast improvements to both the jumpsuit and parachute.