I'm seeking some clarification on the role of the word 'that' in the sentence below.
He persuaded me that he was right.
Is it just acting as a pronoun? Describing whatever he was right about.
(1) I believe that most high-school level books would say that the word "that" in your sentence just connects "He persuaded me" + "he was right."
(2) Some books call it a "subordinating conjunction." Some books call it an "expletive" (because they don't know what other word to call it).
(3) In other words, it is not necessary in your sentence.
(4) In fact, many native speakers in fast conversation don't use it.
(5) Please remember, however, that sometimes the word "that" is important. But we are discussing only this particular sentence.
(6) Check your book for "noun clauses." Usually you don't need "that" when it simply introduces a noun clause.
I hope (that) you have a nice day!