Do you use a comma when saying he said?

You do not use a comma when saying "he said" unless it's in a dialogue tag.

Here's why:

* Dialogue Tag Placement: When "he said" or similar tags follow a complete sentence, you don't need a comma.

* Example: "He went to the store." He said.

* Dialogue Tag Within a Sentence: If the tag interrupts a sentence, you do need commas.

* Example: "He went to the store," he said, "to buy milk."

In short, commas are used to separate dialogue tags from the rest of the sentence, not after the tag itself.