Yahoo! named 37-year-old Marissa Mayer, a key Google team member, as its chief executive, making her among the most prominent women in technology and corporate America.
The appointment effective Tuesday "signals a renewed focus on product innovation to drive user experience and advertising revenue for one of the world's largest consumer Internet brands," Yahoo! said in a statement in San Francisco on Monday.
The move comes as a surprise after many reports said interim CEO Ross Levinsohn had a lock on the top job at the struggling Internet pioneer.
"I am honored and delighted to lead Yahoo!, one of the Internet's premier destinations for more than 700 million users," Mayer said in a statement.
"I look forward to working with the company's dedicated employees to bring innovative products, content, and personalized experiences to users and advertisers all around the world."
At Google, Mayer was responsible for local and geographical products including Google Maps, Google Earth, Zagat, Street View, and local search for desktop and mobile. She joined Google in 1999 as its 20th employee "and led efforts for many of Google's most recognizable products, including the development of its flagship search product and iconic homepage for over 10 years," the statement said.
She also "managed some of Google's most successful innovations, launching more than 100 features and products including image, book and product search, toolbar, iGoogle, Google News, and Gmail," according to the statement.
Mayer told a daily she "had an amazing time at Google" over the past 13 years, but that she opted to go to Yahoo! because it is "one of the best brands on the Internet."
Levinsohn took over in May when Scott Thompson was ousted in the face of controversy about an inflated resume.
Last week, shareholders endorsed the struggling Internet firm's overhauled board of directors and called for a fresh plan to compete against rivals such as Google and Facebook, but made no announcement about a chief executive.
Yahoo! has been trying to reinvent itself as a "premier digital media" company since the once-flowering Internet search service found itself withering in Google's shadow.