Since the moment he dropped out of Harvard University, Mark Zuckerberg has stayed remarkably focused on two things: Facebook, and being the boss of Facebook.

Early on he was persuaded of the vast potential of the social network he built in his dorm room, say friends, investors and detractors. He pushed his team to be fast and take risks. He resisted efforts to change the way Facebook looked and worked, even if, in the beginning, it meant giving up revenue.

Most important, he arranged the ownership of Facebook so as to give himself extraordinary power to steer the company. By the time Facebook filed for a $5 billion public offering on Wednesday, Mr. Zuckerberg had managed to hold on to more than one-fourth of the shares in the company, and his agreements with other investors enhanced his voting power to almost 60 percent of total shares.

That’s a greater measure of control than Bill Gates had at Microsoft when it went public in 1986 (49 percent), and far greater than what the co-founders of Google had in 2004 (16 percent each). Typically, say Silicon Valley veterans, a first-time entrepreneur gets to the public market with a far smaller stake in his or her creation. Mr. Zuckerberg’s arrangement leaves little room for investors to have much input on the company’s direction.