Fresh 16++ Thora Birch The Walking Dead. Thora birch (born march 11, 1982) is an american actress and producer. The thorabirch community on reddit. But then, out of the blue, my people called me and they're like, you know, we got this call from casting from walking dead, and they said. Thora birch is an american actress who portrayed mary in amc's the walking dead. Thora Birch The Walking Dead - The Walking Dead Season 10 Release Date Trailer Cast And Story The Walking Dead Walking Dead Season Fear The Walking Dead Beyond thora birch, the walking dead has added to its ensemble cast elsewhere as well.