Jackson -- who signed a $90 MILLION deal with the Jaguars in the off-season -- met up with his Super Bowl squad at 1600 Pennsylvania for a Bronco reunion ... and raved about meeting POTUS.
"It was awesome man," Jackson told us ... "First black president in history. Just to kind of meet him, shake his hand ... see his aura and his swaginess. It was dope, true blessing."
He also had some nice things to say about his old QB ... check out the clip.