FA lied to captain (claims I directed obscene language at him)
 

sitting in first. Bulkhead aisle and was first to deplane. FA who had been rude all flight rudely again told me to “step back” I told him it wouldn’t hurt to say please and he said he did. I politely but firmly said no you didn’t and after going back and forth asked for his name. When he refuses to give it I asked to speak to the pilot. He went into the cockpit and said “this man just told me to jump off the jet bridge and suck my d—-“. which I most certainly did not.

The captain stepped out out and asked what the problem was. I explained exactly what I posted above and he asked me to step out onto the jet bridge to wait for him. I’m now waiting on the jet bridge. Never in my life have I ever experienced anything like this.

Many suggestions beyond speaking to the captain?

I'm not doubting your story at all, but if what you say actually played out (just unbelievable), you must have realised that this was escalating quickly. Why pick a fight when none is necessary?

Passengers need to be wearing body cams for these situations!

Time to:

Calm down

Back down

Apologize

Very much this, other pax would have had to have heard the interaction and you’re gonna need someone to collaborate since it seems this FA has no issue, and likely more experience, lying

Unfortunately (unless he asked them right away), once he got out on the jetbridge, everyone who was close enough to hear probably went past him within 60 seconds.

“Ground security supervisor” came into jet bridge and took a formal complaint. Said he would file complaint on my behalf and advised me how I could also do so online.

Turns out female FA heard everything. After I finished speaking to the “ground security supervisor” I was walking out and she apologized to me. Not sure if she’ll corroborate on record or not but makes me feel a little better. Will definitely file a formal complaint. Still in shock.

For his part in escalating, but not for saying something he didn't say, right? If the captain asks "did you say that?" you don't expect him to say "yes, and I'm very sorry"?

I disagree here. I'd never apologize for someone being rude to me. But you do need to evaluate what escalating will get you, especially when dealing with a liar.

I hope OP started recording once on the jetway.

I wonder what would happen if you refused to board a future flight with the same FA? I doubt his lying will have stopped but you get on record as having an issue there.

just to de-escalate the situation. Ultimately your goal is to get to your destination. So do what you can to ensure you do just that and file a complaint later.

^ Hope you have the name of the supervisor and/or the female FA who can corroborate?

I think JonNYC meant before it got to that point. Meaning if the FA was rude, getting into a back and forth is a dangerous game. If they respond combatively, then dont reply.

better to handle it after the fact that get into a he said -she said and potentially get booted off the airplane (independent of who was in the right and wrong).

to the OP - sucks this happened. Definitely file a complaint with as much pertinent details as possible.

Perhaps, but OP's original question was essentially "what do I do now?", and JonNYC's answer started with "Time to:" which I read as "Now (the upcoming conversation with the captain) is the time to:".
But the plane had landed so that's not much of a threat. :) The risk in this situation would be if OP had an onward flight that AA could mess with, or if the police were called.