The Los Angeles Times said the cause of Moody's Tuesday night death was not immediately known.
"WWE is saddened to learn of the passing of William Moody, a.k.a. Paul Bearer," the WWE said in a statement.
"Moody made his WWE debut in 1991 as the manager of The Undertaker and went on to become a memorable part of WWE over the course of the next 20 years. Our deepest condolences go out to Moody's family, friends and fans."
He is survived by his sons, Michael and Daniel, the Times said.