Here is a list of 9 campground in the Smokey Mountains that are pet friendly.  They have a wide range of prices and ammenities. Hope it helps.

Arrow Creek Campground -4721 E Parkway  Gatlinburg
http://www.arrowcreekcamp.com/
Dogs of all sizes and numbers are allowed for tent and RV sites. There are no additional pet fees. Dogs may not be left unattended, must be quiet, leashed, and cleaned up after. The camping and tent areas also allow dogs. There is a dog walk area at the campground.

Great Smoky Jellystone -4946 Hooper H  Gatlinburg
http://www.greatsmokyjellystone.com/
Dogs up to 75 pounds are allowed. There are no additional pet fees. Dogs must be well behaved, not left unattended, be leashed, and cleaned up after. There are some breed restrictions. There is a dog walk area at the campground.

Great Smoky Mountain National Park -107 Park Headquarters Road  Gatlinburg
http://www.nps.gov/grsm/planyo.....t/pets.htm
I personally don't think this place is pet friendly, but they do allow pets.
Dogs are allowed along roadways, picnic areas, waterways, on only 2 of the many trails, and the camp area. Dogs must be leashed and under their owner's control at all times. The camping and tent areas also allow dogs. There is a dog walk area at the campground. There are no electric or water hookups at the campgrounds.

Smoky Bear Campground -4857 E Parkway  Gatlinburg
http://www.smokybearcampground.com/
Dogs of all sizes are allowed at the tent and RV sites. Small dogs only are allowed in the rentals or cabins. There are no additional pet fees. Dogs may not be left unattended except for very short periods. Dogs must be leashed and cleaned up after. The camping and tent areas also allow dogs. There is a dog walk area at the campground.

Twin Creek RV Resort -E Parkway  Gatlinburg
http://www.twincreekrvresort.com/
I personally don't this place stinks, but they do allow pets.
Dogs of all sizes are allowed. There are no additional pet fees. Canvas or Pop-up trailers are not allowed with pets. Dogs may not be left unattended, and dog pens are not allowed. Dogs must be leashed and cleaned up after. There are some breed restrictions. There is a dog walk area at the campground.

Riveredge RV Park -4220 Huskey Street  Pigeon Forge
http://www.stayriveredge.com/
Dogs of all sizes are allowed. There are no additional pet fees. Dogs must in your RV and not left outside alone when gone. Dogs must be leashed and cleaned up after. There is a dog walk area at the campground.

River Plantation RV Park -1004 Parkway  Sevierville
http://www.riverplantationrv.com/
Dogs of all sizes are allowed. There are no additional pet fees. Dogs must be leashed and cleaned up after. There is a dog walk area at the campground.

Townsend / Great Smokies KOA -8533 H 73  Townsend
http://koa.com/campgrounds/tow.....t-smokies/
Dogs are allowed for no additional fee. Dogs may not be left unattended outside, and they may only be left alone inside if they will be quiet. Dogs must be on no more than a 6 foot leash and cleaned up after at all times. There are some breed restrictions. The camping and tent areas also allow dogs. There is a dog walk area at the campground.

Tremont Hills Campground -118 Stables Drive  Townsend
http://www.tremontcamp.com/
Dogs of all sizes are allowed. There are no additional pet fees. Dogs may not be left unattended, and must be leashed and cleaned up after. The camping and tent areas also allow dogs. There is a dog walk area at the campground.