Google Inc. (NASDAQ:GOOG) made headlines on Thursday after the market closed when it unveiled fourth-quarter results that handily beat expectations and announced a management shake-up that removes chief executive Eric Schmidt from his post.

Beginning on April 4, Larry Page, one of the co-founders of Google, will take over the day-to-day operations as chief executive, the company said. Schmidt will take on the role of executive chairman, and co-founder Sergey Brin will work on new products and strategic projects.

Shortly after the announcement, Schmidt released a statement via Twitter, explaining that “day-to-day adult supervision [is] no longer needed.” Schmidt attributed the management shake-up to the company’s need to simplify management structure and speed up decision making, saying the three executives agreed over the holidays to clarify their individual roles to make certain that responsibility and accountability at the top of the company is clear.

“I am enormously proud of my last decade as CEO, and I am certain that the next 10 years under Larry will be even better!” Schmidt said in the release. “Larry, in my clear opinion, is ready to lead.”

Schmidt went onto explain that as executive chairman his focus will be directed externally “on the deals, partnerships, customers and broader business relationships, government outreach and technology thought leadership that are increasingly important given Google’s global reach.” Schmidt said he will also continue to serve as advisor to Page and Brin.

In a release, Page said Schmidt had done an “outstanding job” leading the company.

“The results speak for themselves. 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,” Page said. “Eric is a tremendous leader and I have learned innumerable lessons from him.”

In regard to the company’s results, Google was widely expected to meet or beat fourth-quarter expectations by posting a sharp rise in profit during the quarter as a result of increased demand for advertising on its search engine.

The search engine behemoth did not disappoint, posting net income of $2.54 billion, or $7.81 a share, up from year-ago profit of $1.97 billion, or $6.13 a share. On an adjusted basis, earnings rose to $8.75 a share, from $6.79 in the fourth quarter of 2009. Net revenue, which is revenue excluding traffic acquisition costs, rose to $6.37 billion, compared with sales of $4.95 billion in the year-ago quarter.

The results easily topped expectations, as analysts polled by Thomson Reuters had predicted $8.10 a share on revenue of $6.06 billion. The company also beat the whisper number of $8.40 a share, according to WhisperNumber.com.

International revenue grew to $4.38 billion, totaling 52% of total revenues in the fourth quarter, which compares to 53% of total revenue in the year-ago quarter. Paid clicks rose 18% compared to the fourth quarter of last year, and 11%, sequentially. Average cost-per-click increased 5%, year-over-year, and rose 4% compared the third quarter of 2010. 

Shares of Google fell $4.98, or near 1%, in Thursday’s session, closing at $626.77. The stock was up $15.22, or 2.3%, in after-hours trading.