When you think of Facebook boss Mark Zuckerberg, you likely envision the software coder portrait of him from The Social Network. That dramatization is no caricature. As I note in my Fortune feature article about Zuckerberg, released online today, he even analogizes the role of big-company CEO to that of writing code: You break down a complex set of tasks into smaller tasks and then attack them methodically. Only a committed engineer-turned-entrepreneur would verbalize it that way.

But what about Zuckerberg the businessperson? That, it turns out, is the overlooked aspect of his role at Facebook. In fact, he is Fortune’s 2016 Businessperson of the Year, recognized for his company’s stellar financial performance, market heft, and innovative ways. The case I make in my article is that it’s easy to miss Zuckerberg’s business chops because of the prominence of his MBA deputy, Sheryl Sandberg, who runs Facebook’s business operations. And yet it is Zuckerberg who has held together an extraordinarily long-tenured management team and made critical strategic decisions for Facebook over its 12-year existence.

The stability at the top is no trivial matter. Toward the end of his 15-year second act at Apple, Steve Jobs commanded a senior management team that had been with him nearly the entire time. Zuckerberg’s reign so far is a little shorter, but already his top people have been along for most of the ride. It’s a hallmark of good leadership to be able to attract and retain top talent. (A rising stock price helps too.)

Zuckerberg, at the tender age of 32, faces plenty of challenges. Facebook enjoys the giant benefits that accrue to being a media titan even as it shrinks from the attendant responsibilities. If Zuckerberg doesn’t rise to the occasion, Facebook could lose the trust its 1.8 billion users place in it.

For all his consistency, Zuckerberg today is a more mature—and richer—version of the insouciant entrepreneur I first interviewed in 2005, when he memorably handed me a business card with a vulgarity printed on it that would never fly now. He and his company have come a long way.

Adam Lashinsky
@adamlashinsky
adam_lashinsky@fortune.com