Johnson's Baby Powder was first produced in 1890 as a result of one of the family's brothers reading a report from an Italian doctor about skin irritation in youngsters.
It occurs naturally as a mineral, I don�t think anyone �invented� it as such, perhaps patented or bottled it first but I think the use of �talc� goes way back to Egyptian, Greeks and Roman�s and probably before that, by grinding down magnesium minerals.
But as said above, if you must find an inventor in modern times, then perhaps Fred B. Kilmer who pioneered Johnsons Baby Powder by adding scent to Italian talc, back in 1890.