SAN FRANCISCO — Eric Schmidt, a technology veteran brought in as Google Inc.'s "adult supervision" a decade ago, is relinquishing the CEO job to Larry Page, one of the prodigies who co-founded the company behind the Internet's dominant gateway.

SAN FRANCISCO — Eric Schmidt, a technology veteran brought in as Google Inc.'s "adult supervision" a decade ago, is relinquishing the CEO job to Larry Page, one of the prodigies who co-founded the company behind the Internet's dominant gateway.

The surprise shake-up announced Thursday appears to be driven by Schmidt's desire to tackle other challenges as much as Page's personal ambition.

"Day-to-day adult supervision no longer needed!" Schmidt wrote on his Twitter account moments after Google dropped the bombshell that upstaged its fourth-quarter earnings. Schmidt, 55, will still be available to advise Page, 37, and Google's other 37-year-old founder, Sergey Brin, as the company's executive chairman.

Under the new pecking order effective April 4, Page will reclaim the CEO job that he held for three years before Google's investors insisted that a more mature leader be brought aboard. That led to the 2001 hiring of Schmidt, a professorial engineer who had previously held top executive jobs at Sun Microsystems Inc. and Novell Inc. After initially resisting Google's overtures, Schmidt bonded with Page and Brin to form a brain trust that proceeded to build the Internet's most powerful company.

Google now boasts a market value of more than $200 billion, a success story that has minted Page, Brin and Schmidt among the world's wealthiest people. The three men are Google's largest individual shareholders, stakes that turned them all into multibillionaires.

The management reshuffling appears to be amicable. Both Page and Schmidt had high praise for each other during a Thursday conference call with analysts, with Schmidt describing Google's co-founders as his "best friends."

"I believe Larry is ready" to be CEO, Schmidt said during the call. "It's time for him to have a shot at running this."