​He was a Steeler, and then he was done. And then he wasn't. 

And Steelers fans got really, really mad.

But following a brief coda to his career in which he donned a New England Patriots jersey in a failed quest to secure one last Super Bowl championship, legendary linebacker James Harrison is ready to call it quits for real this time.

​He took to Instagram to share the news.

As Harrison's caption reads:

I've missed way too much for way too long...and I'm done. Many thanks to my family, coaches, the fans, and everyone who played a role in my football life. #2ndAndFinalRetirement #HarrisonFamilyValues #BlessedAndHighlyFavored #GodsPlan 

Doing it for the kids is the best possible reason.

A 15-year veteran, Harrison hangs it up as a five-time Pro Bowler and the 2008 Defensive Player of the Year. Though he had brief forays with the Ravens, Bengals, and Pats -- as well as the Rhein Fire of NFL Europe, believe it or not -- his best years were no doubt in Pittsburgh, with whom he won two Super Bowls, XL and XLIII, capping the first ring with a mad dash on a 100-yard interception return to close the first half and change the entire game.

Given the nature of his final exit from the Steelers and his instant embrace of New England, it will likely take some time before the Black and Yellow faithful come back around on Harrison. But his on-field legacy is unimpeachable, full stop. In the big picture, football fans are waiving goodbye to a true original whose dominance and fearsome reputation will stick in their memory like few others.