Law enforcement discovered Hardwick’s body during a welfare check at the actor’s Texas home on Tuesday, according to TMZ.
Hardwick was pronounced dead at the scene but the cause of his death was not revealed immediately.
Before Hardwick landed his role as Dale on "King of the Hill," he started his career as a stand-up comedian, according to Variety.
Hardwick eventually landed a performance on "The Jon Stewart Show" and would go on to make appearances at famed comedy clubs such as the Laugh Factory in Los Angeles.
He was quickly noticed by "Beavis and Butt-Head" creator Mike Judge and "The Simpsons" screenwriter Greg Daniels, who were working to create "King of the Hill" in the late ‘90s, according to IMDB.
Judge and Daniels invited Hardwick to join the show, which ran for 13 seasons and won two Primetime Emmys.
Hardwick was slated to reprise his role as Dale in the "King of the Hill" reboot on Hulu, which was announced earlier this year, Variety reported.
Other projects Hardwick worked on include "Natural Selection" and "The Collegians Are Go!!"
This story was reported from Los Angeles.