There was a definite yin and yang as the show began in the Seattle Centre Pavilion, adjacent to the KeyArena.
A stone-faced MacDonald, dressed impeccably in suit and tie, stared at the audience as if he was attending a sentencing hearing rather than promoting an MMA card.
Penn, whose wardrobe selection consisted of finding a bjpenn.com T-shirt to wear, was the picture of relaxation until midway through the news conference when asked about his reaction to comments from MacDonald.
"Rory said he took this fight because he really wants to hurt me. He said I'm probably going to die in the ring and he better be ready to back up everything he said," said Penn, his eyes burning like a laser in MacDonald's direction.
Asked if he felt disrespected, the 33-year-old Penn didn't bite but repeated that the 23-year-old Canadian had better back up his comment on Saturday in the cage.
"I'm ready," replied an icy MacDonald. "Don't worry about that."
The debate went downhill after that.
"We'll see," said Penn.
"We will see," answered MacDonald.
"Can't wait, buddy," said Penn.
Penn's took some licence with his quoting of MacDonald, a native of Kelowna, B.C., who fights out of Montreal. Asked Wednesday about his thoughts on Fox's "Road to the Octagon" preview show. MacDonald said Penn, a former lightweight and welterweight champion, is fighting for the wrong reasons and will pay for it Saturday.
Penn (16-8-2) is in search of status or legacy, the young Canadian said.
"I'm fighting to hurt him," MacDonald said. "Not fighting for someone's opinion.
When Penn and MacDonald went to pose for the traditional photo after the news conference, White wasted little time sticking a hand between the two to prevent any physical contact. The two fighters kept their cool but there was no handshake.
McDonald (13-1) did not back down Thursday on the issue of Penn fighting to get his legacy back.
"I don't know if that's his motivation to fight or not but if that is true, you're fighting for someone's opinion, for status, it's the wrong reason to fight. But his motivation may be something else altogether.
"If that is his motivation, I think it's going to get him hurt."
White said what he took out of Penn's statement on the TV show was that the Hawaiian could have enjoyed even more success if he had taken his sport more seriously.
"B.J., he's at this point now where he's like 'All right, I get it. The (championship) belt, I didn't appreciate the belt when I had it. Now that it's gone, I get it. And I'm not too old, I'm still young enough to go on one of these type of (winning) streaks and claim my spot in history.' That's how I took it."
Is that right, White then asked Penn.
"Yes sir," was the reply.
The Penn-MacDonald interplay overshadowed the other fighters on the podium: lightweight champion Benson Henderson and challenger Nate Diaz in the main event, and former light-heavyweight champion Mauricio (Shogun) Rua and Alexander (The Mauler) Gustafsson in the co-main event.
Penn has not fought since retiring in the cage in October 2011 after a lopsided loss to Nick Diaz, Nate's older brother. At five foot nine, he is giving up three inches, 10 years and probably close to 20 pounds fight night to the Canadian young gun.
Penn may be the underdog but, as White noted, fans still have a special place for Penn.
"The fans love B.J. Penn. You know why they love B.J. Penn? Because of what you saw up here today (at the news conference)."
"He called Rory out," added White, who got a text from the Hawaiian to ask for the matchup. "B.J. Penn is a maniac, man. He loves to fight. He's a warrior."
The choice of MacDonald continues Penn's competition with Montreal's Tristar Gym, home to welterweight champion Georges St-Pierre. Penn, who once fought Lyoto (The Dragon) Machida at heavyweight, has lost twice to GSP.
"Whatever this kid wants to do," White said of Penn. "He's proven himself time and time again, he can hang with anybody.
"Has he taken a couple of beatings? Yes. And I blame him for that. Not his talent. ... He was so talented he never took this thing seriously, never trained and applied himself as hard as he could have. If he would have, he would have been the guy with the 10-, 15-, 20-fight win streak and he would be still be talked about as one of the greatest ever."