83 sorc, finished through Hell, never bothered to loot/save a Leg in any mode. Stash definitely does not have one.
I checked all 3 modes now
So how exactly do you get Wirt’s Leg if you didn’t pick it up the first time through any of the 3 modes?
It’s not a drop. There is a dead body which drops it every time with a bit of gold.
The body can be found in the opposite corner of where you enter Tristram.
Cain still needs his legs.
I’ll just reiterate what others have said. The tristram portal is always open once you opened it. Just head over to the stony field to find the portal go in and grab the leg. It’s gonna be there every game.
When someone makes a cows game, the first thing they do is go to tristram to get the leg again.
Ah thanks, I forgot they changed it so you can make Cow games any time.
The body you are looking for is in the far back left corner on the ground near some carver type little demons. I think it is labeled as Wirt or something. Keep in mind you can only have one leg in inventory at once. As Kal said, Deckard Cain still needs his legs so does not drop one.
I get a bit wobbly in the ole legs once I’ve had a few wines.
He’s a character from Diablo 1. Every time you went to town he would have a premium item that was usually better than anything you could buy at Griswold. He charged you money just to show you the item.
That’s why he drops a bunch of gold when you loot him. It’s a joke. You’re presumably looting all the gold that people gave him to look at the item he was selling.
I know 
I just can’t remember if the D2 body is labeled as being Wirt or just “body”.
The story is great to share though! I bet there are many folks who have forgotten, or were too young to have played. He most certainly deserved to die and give back some of the money!
Reset the game and go fetch it!
Wirt deserved what he got, little shyster. Griswold not so much he was an honest dude.