It will be too thick to fit in the HDD cage in the G75. Probably too thick to fit even without it. A 12mm drive MIGHT fit, but this is a 15mm drive. You can always take the bottom panel off your G75 and measure the space available. Without even looking, I'm about 90% sure it won't fit.
EDIT: Upon further reading of the item description, I noticed this:
*Cannot be used in laptop or notebook computers. Designed for PCs and custom external enclosures. Consult system specifications for maximum allowable drive height before attempting to install.
Here's a 1.5TB drive that will fit:
http://www.amazon.com/gp/product/B00EDIU5IW/ref=s9_hps_ft_g147_ir17?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=ce...What capacity drives do you have in your G75 now?
ASUS G75VW
i7-3630QM 2.4Ghz
GTX 660M (2GB)
16GB DDR3 1600Mhz
1TB HDD
2TB HDD
Blu-ray Writer (Pana. UJ-260)