“This just might do nobody any good” is a chancy first line for a play.

Or maybe not too chancy at that, when the man who delivers it is George Clooney, and the man he’s portraying is Edward R. Murrow. This is, after all, Broadway, where glossy demigods of the left are loved.

Still, Clooney has never previously appeared on its stages — “so … buckle up,” he writes in his bio.

That Murrow has him beat in that regard, having appeared as a character in a musical called “Senator Joe,” is not surprising. He was, after all, a world-famous journalist whose first name might as well have been “crusading.” As “Good Night, and Good Luck” begins, what he’s crusading for, in a speech to news directors, is a complete rethink of television, which in choosing to “distract, delude, amuse and insulate” is making Americans “fat, comfortable and complacent.”

That’s in 1958. Looking at the diminished state of television news today, you’d have to conclude he was right: His speech did nobody any good.

But his journalism is another story, and that’s the one “Good Night, and Good Luck,” which opened on Thursday at the Winter Garden, wants to tell. To do so, it quickly jumps back to 1953 and into CBS’s Studio 41, where Murrow and his producer, Fred W. Friendly, run the small empire that creates the newsmagazine “See It Now.” They are about to embark on a series of broadcasts designed to unmask, and thus destroy, Senator Joseph R. McCarthy, the Communist-witch-hunting demagogue. Amazingly, they succeed.