Russell's a great actor, it's a shame he didn't have many more starring roles. Rod Serling indeed died way too young. It would had been great if decades later. He could had done a newer version of the Twilight Zone in the late 70's or the 80's version. Russell was great in McArthur 1977 starring Gregory Peck.
Rod Serling may have smoked himself to death, but Russell Johnson advertised Raleighs. I guess his point was that Serling kept smoking long after its dangers were known, while Johnson didn't keep doing ads for Raleighs.