Prepare the brine by mixing 4 cups of water, 1/4 cup of kosher salt, 1/4 cup of brown sugar, 2 tbsp of black pepper, 2 tbsp of paprika, 2 tbsp of garlic powder, 1 tbsp of onion powder, and 1 tsp of cayenne pepper in a large container.
Place the top round steak into the brine, making sure it is fully submerged. Cover and refrigerate overnight.
Preheat your pellet smoker to 225°F.
Remove the top round steak from the brine, rinse, and pat dry with paper towels.
Combine dry rub ingredients and season the entire surface of the top round steak
Place the top round steak onto the smoker grates and smoke for 4 hours or until it reaches an internal temperature of 135°F for medium-rare. (Check the internal temperature with a meat thermometer every 30 minutes as it nears the end)
Remove the smoked top round steak from the smoker and let it rest for 10 minutes before slicing.
Slice the smoked top-round steak against the grain and serve.