Yet the four-time Pro Bowler knows that fury has its limits, and Friday he admitted he blew right past them in a magazine article earlier this month in which he used an anti-gay slur when talking about commissioner Roger Goodell and criticized teammates for their play in Pittsburgh's Super Bowl loss to Green Bay.
"The comments I made about Roger Goodell were inappropriate at the least and way out of line," Harrison said. "I was speaking out of anger and frustration at the time and any comments that I may have made that offended anyone with my careless use of words, I apologize."
Harrison used the slur while expressing his frustration over the league's new player safety rules. One of the NFL's fiercest hitters, the volatile 33-year-old drew $100,000 in fines for illegal hits last season. He thought he was venting about the new rules — and not Goodell personally — while calling him a "crook" and a "devil."
It didn't read like that, and Harrison allows he should have used a "better vocabulary" when talking about the issue and the commissioner.
The 2008 AP Defensive Player of the Year hasn't spoken to Goodell since the article was published and isn't sure whether he'll be disciplined by the league.
"I don't think (Goodell) is a guy that's going to hold something on a personal level (against me professionally)," Harrison said. "I attacked him on a personal level, which wasn't right. I don't expect anything to be done."
There's also the question on whether Goodell would even have the power to suspend or fine Harrison.
The comments were made during the NFL lockout, meaning technically Harrison wasn't working for the league at the time. Harrison said he wouldn't decide whether to fight any penalty until it is levied.
The team has not indicated it will discipline Harrison, though coach Mike Tomlin agreed with Harrison's assessment that his words were inappropriate. Harrison spoke to owner Art Rooney recently but hasn't been excluded from any team activities as the defending AFC champions opened training camp.
One place where the article didn't create a stir appears to be the locker room. Harrison reached out to running back Rashard Mendenhall — whom Harrison called a "fumble machine" — and quarterback Ben Roethlisberger — whom Harrison said needed to "stop trying to act like Peyton Manning" — after the article came out.
Both players said there were no hard feelings and are well aware that Harrison's temper can sometimes get the best of him.
"He called me that morning (the article came out) and left me a voice mail because he was sure I wanted to talk to him and I had no idea what he was talking about," Roethlisberger said. "So I called him and he explained everything and it literally was nothing, absolutely no linger effects whatsoever."
Roethlisberger threw a pair of interceptions in Pittsburgh's 31-25 loss to the Packers, with both picks leading to touchdowns. The way the quarterback looked at Harrison's outburst, all he was doing was stating the obvious.
"No one is going to be harder on me than I am and I told James, I told everybody that it was my fault we lost the Super Bowl anyway, so if he wants to reiterate what I said, that's fine," Roethlisberger said.
The players appear eager to put the incident behind them and move forward, though Harrison is hardly the only Steeler to make waves off the field during a bumpy offseason for one of the league's marquee franchises.
Wide receiver Hines Ward won "Dancing With the Stars" then was arrested for DUI in Georgia, a charge that drew national headlines and took some of the shine off Ward's image as a humble and hard-working team leader. He declined to talk specifics about his arrest, but understands why it was a big deal.
"That's what comes with it, the price of fame," Ward said. "Every little thing you do is in the media eye and the public's eye. For me it's a learning process. You can't be one of the boys and do things, you have to look at the big picture. I'm confident in the end that everything will work out."
Mendenhall, like Roethlisberger, shrugged off Harrison's jabs. He also declined to expound on his controversial tweets following the death of Osama bin Laden in April. He's only too anxious to move forward.
So is the team, which continued a flurry of activity by releasing veteran offensive tackle Flozell Adams early Friday morning. The 36-year-old Adams became expendable after the team agreed to terms with Willie Colon and Jonathan Scott late Thursday night.
Colon and Scott, along with the team's other signings, can't practice until next week, meaning things will be very much in flux as they begin the process of trying to get back to the Super Bowl.
The loss to the Packers has hung with Roethlisberger for months. Even his wedding last week to Ashley Harlan, a physician assistant, hasn't made him forget about his disappointment in Dallas.
"We can't dwell on the past," he said. "We have to focus on the future and what's to come."