>>Johnson appeared in two episodes in The Twilight Zone.
You beat me to it. And you of course got both correct. Did you actually remember him being in these 2? I initially forgot the one about the execution.
I remembered only vaguely. I was already reading about him online and came across The Twilight Zone details. He was 89.
He also co-starred with William Shatner in a classic “Thriller” tv show hosted by Boris Karloff.
Years ago I was watching in a theater a double feature showing old sci fi classics from the 1950s in 3D. One of them was It Came From Outer Space and Russell Johnson has a bit part in it. Unless you were paying attention to the credits you wouldn’t have been expecting him to show up but when he did a large number of the audience yelled out in unison It’s The Professor!!!. I still get a chuckle out of that spontaneous moment in my movie going life.