SAN FRANCISCO — Google unveiled a surprise shakeup of its top management on Thursday, announcing that co-founder Larry Page would replace Eric Schmidt as chief executive of the Internet giant in April.

Schmidt, who has served as Google's high-profile CEO for a decade, would remain with the Mountain View, California-based company as executive chairman, focusing on partnerships, customers and government outreach, Google said.

Schmidt, 55, will also act as an advisor to Page, 37, who served as CEO previously, from 1998 to 2001, and Google's other co-founder, Sergey Brin, Google said in a statement.

Google said Brin, also 37, will work on strategic projects and new products, what he described in a conference call with financial analysts as his "personal passions."

Google said the management changes would take effect on April 4.

"Day-to-day adult supervision no longer needed!" Schmidt said in a message on his Twitter feed @ericschmidt.

The unexpected shakeup in the "triumvirate" at the top at Google overshadowed the company's announcement of its fourth quarter results.

Google said net profit rose to $2.54 billion in the fourth quarter from $1.97 billion in the same quarter a year ago while revenue climbed 26 percent to $8.44 billion over a year ago.

Technology bloggers and analysts were uncertain what exactly to make of the management shakeup at the company which dominates the search engine market but has been coming under pressure from social networking rivals such as Facebook.

Danny Sullivan, editor-in-chief of technology blog, said Google's "probably overdue for a major management reorganization."

"The structures between the three have remained exactly the same over the past 10 years -- which might as well be 100 years of Internet time," he said in a blog post.

"It could be that Schmidt wants a break from being the main public face of the company," he said.

Sullivan noted that Schmidt had come in for criticism for awkward recent statements which had been "harmful to Google's reputation" and the three top executives may have decided "it was time for a fresh public face."

John Battelle, author of "The Search," a book about Google and technology rivals, said: "Eric has been at it for a decade, a very long time to be running a company, particularly one that has very headstrong founders in key positions of power."

"I think it's fair to say that Larry Page will not be a conventional CEO -- he's not been much of a public figure for the past ten years," Battelle added on his blog,

"It will be interesting to see if that changes, or if Page chafes at the relentless public demands of running a massively scrutinized public company."

Schmidt, in a blog post, said: "Larry, Sergey and I have been talking for a long time about how best to simplify our management structure and speed up decision making."

"For the last 10 years, we have all been equally involved in making decisions," he said.

"This triumvirate approach has real benefits in terms of shared wisdom, and we will continue to discuss the big decisions among the three of us.

"But we have also agreed to clarify our individual roles so there?s clear responsibility and accountability at the top of the company," Schmidt said.

"Larry, in my clear opinion, is ready to lead," he said. "Larry, Sergey and I have worked exceptionally closely together for over a decade -- and we anticipate working together for a long time to come."

Page praised Schmidt for an "outstanding job leading Google for the last decade.

"There is no other CEO in the world that could have kept such headstrong founders so deeply involved and still run the business so brilliantly," he said.

"Eric is a tremendous leader and I have learned innumerable lessons from him. His advice and efforts will be invaluable to me as I start in this new role," he said.

Google shares were up 1.96 percent to $639.05 in after-hours electronic trading after the strong earnings results and management shakeup were announced.