Green’s Dictionary of Slang

(US) an excl. used to express surprise.

1957		Laurents & Sondheim West Side Story II i: They say go earn a buck, / Like be a soda jerker, / Which means like be a schmuck. / It’s not I’m anti-social, I’m only anti-work. / Glory Osky, that’s why I’m a jerk!
1995		R.R. Johnson Twenty Five Milk Runs (and a Few Others) 80: ‘Gloriosky,’ as Little Annie Rooney would say, ‘I made Second Lieutenant.’.
2004		A. Horn Face It 129: The number of solar systems in this galaxy, and the number of galaxies in this universe, and the possible number of dimensions in the world, well glorioski!