Lay the backstrap on the counter and remove any silver skins or thin pieces of the meat. If you don't remove those, the meat will cook uneven or become tough and not pleasant to chew.
Mix together the soy sauce and Italian dressing. Place Venison in a shallow pan for marinading. Pour marinade on top and refrigerate for 2 hours.
Remove meat from marinade and pat dry with paper towels. In a small bowl, mix together salt, pepper and garlic powder. Season all sides of the backstrap with the seasoning.
Preheat your gas or charcoal grill to 400°F. Place meat on the hot part of the grill and cook every side (including the top and bottom) so you have some charr or a sear from the heat. Once the thickest part of the meat reaches 115°F, pull the meat off the grill.
Last and most important step is to let it rest for at least 10 minutes and honestly I will let it rest sometimes for 15 minutes so that the juices and flavor within the meat settle and won’t end up all over your cutting board.