BIG man on campus

It was a serious mismatch.

The brainiest and most reflexively skeptical corner of the Hub simply swooned. And Boston’s newest Celtic took it all in stride — indeed, one giant stride after another.

He arrived without celebrity entourage — no publicist, no handlers, no burly security — and soon had a mob of students, tourists, and shoppers trailing in his vast wake. The growing crowd followed O’Neal from Widener Library through Harvard Yard to the Harvard Book Store, disbelieving what they saw. They directed cameras and shout-outs his way. Everyone wanted a piece of the 7-foot-1 megastar, and just about everyone got one.

Hardly anything stops the traffic chaos of the Square. But when Shaq dropped his formidable frame onto a bench, the crowd swarmed and traffic stopped.

“It’s like this in every city, every country,’’ said O’Neal. “I read on the Internet that I’m the third most recognized face in the world.’’

O’Neal, 38, who signed a two-year, $2.8 million contract with the Celtics this month, brings to town a brand of sports celebrity rarely seen in these parts. He wears his colossal fame with remarkable ease. His persona, he says, is the natural byproduct of a never-ordinary life.

“People see me as touchable and real,’’ said O’Neal. “I make them feel like I know that guy. You’ve got to be yourself. A lot of athletes make the mistake of trying to build their brand. I built my brand just by playing and being myself. People who have the most successful image live by what I live by. Image is reality. A lot of stuff I do, I’ve been doing since I’ve been 8-years-old.’’

And for him, that often means playing the comedian. He is a pretty funny guy, and he knows it.

“My mother told me, ‘You are so funny it’s either going to get you in trouble or make you a lot of money one day,’ ’’ said O’Neal.