J.R. Ewing was a business cheat, faithless husband and bottomless well of corruption. Yet with his sparkling grin, Larry Hagman masterfully created the charmingly loathsome oil baron – and coaxed forth a Texas-size gusher of ratings – on TV’s long-running and hugely successful nighttime soap, “Dallas.”

Although he first gained fame as nice guy Major Tony Nelson on the fluffy 1965-70 NBC comedy “I Dream of Jeannie,” Hagman earned his greatest stardom with J.R. The CBS serial drama about the Ewing family and those in their orbit aired from April 1978 to May 1991, and broke viewing records with its “Who shot J.R.?” 1980 cliffhanger that left unclear if Hagman’s character was dead.

The actor, who returned as J.R. in a new edition of “Dallas” this year, had a long history of health problems and died Friday because of complications from his battle with cancer, his family said.