"person or thing that people hope will be very successful in the near future," 1911, originally in U.S. sporting use in reference to the quest for a white man capable of beating champion pugilist Jack Johnson.
The white collar men are your clerks; they are your bookkeepers, your cashiers, your office men. We call them the 'white collar men' in order to distinguish them from the men who work with uniform and overalls and carry the dinner pails. The boys over on the West side got that name for them. It was supposed to be something a little better than they were. [Malcolm McDowell, quoted in Chicago Commerce, June 12, 1914]
White-collar crime attested by 1957 (there is a white-collar criminaloids from 1934).
Old English snawhwit (glossing Latin niveus), from snow (n.) + white (adj.). Similar formation in Dutch sneeuwwit, Middle Low German snewhit, German schneeweiss, Old Norse snæhvitr, Swedish snöhvit, Danish snehvid. The fairy tale is so-called from 1885, translating German Schneewittchen in Grimm; the German name was used in English by 1858.