Hello
"Enchant Ware" trademark was filed October 25, 1960, registered August 8, 1961 and inactivated in July 1994. The registration was for use with "table glassware, and glass tumblers in carriers". First use was reported as at least as early as June 25, 1959. This is the first label I have seen.
The Kenneth M. Smith Co. was a glass decorating firm located in Leaside, Ontario, Canada. I am pretty sure that the firm started out as York Glass Company, Limited because Kenneth M. Smith was also the owner of this firm and in 1939 it was located at the same address as the Kenneth M. Smith Co. They did some nice sandblast/engraving work during the early war years (1940s) but I can't find much between then and the Enchant Ware.
A point of trivia - Ian Tyson was employed by Kenneth M. Smith Co. to "design peanut butter jars and all that stuff..." before his singing career with Sylvia Fricker took off.
Sid