In a mixing bowl, make your marinade. Whisk together the olive oil, apple cider vinegar, soy sauce, Worcestershire sauce, rosemary, garlic powder, black pepper, and onion powder until well incorporated.
Place the venison loin in a large zip-top bag and pour the marinade over the meat.
Seal the bag, transfer it to the refrigerator, and marinate for a minimum of 3 hours, or overnight.
When you’re ready to cook the venison, remove the meat from the marinade bag and season it with salt and pepper. Let the venison rest at room temperature for 30 minutes before smoking it.
Preheat the smoker to 225 degrees Fahrenheit.
Place the venison roast directly on the grill grates over indirect heat and close the smoker lid.
Smoke the venison until a meat thermometer inserted through the thickest part of the roast reads 140 degrees Fahrenheit, about 2 hours.
Remove the venison from the smoker and let it rest on a cutting board for 15 minutes before slicing and serving immediately.