Ms Mayer, 37, edged out front-runner and acting chief executive Ross Levinsohn to become Yahoo’s third CEO in a year. She hopes to stem losses to Google and Facebook – which her high-profile predecessors failed to do.
Her hiring signalled the internet company is likely to renew its focus on web technology and products rather than beefing up online content.
Mayer, Google’s 20th employee and first female engineer, has led a number of its businesses, and was credited for envisioning the clean, simple Google search interface still in use today, a major selling point for web surfers.
Also known for her love of fashion and a regular on the society pages, she joins the extremely thin ranks of female Silicon Valley CEOs and said that she was immediately interested when Yahoo’s board reached out to her in mid-June.
“This is a very competitive and a tough space. I don’t think that success is by any means guaranteed,” she said.
“My focus is always end-users, great technology and terrific talent.”
“It’s a statement on Yahoo’s part to go with a product-centric CEO choice. It’s a very big commitment on the board’s part to pursue a product-centric strategy,” venture capitalist Marc Andreessen told an industry conference in Aspen, Colorado.
Tech companies can be turned around, he said, citing as an example Apple, which had teetered on the brink of bankruptcy before Steve Jobs returned to the company he co-founded.
“It’s a big job that Marissa is stepping into,” Mr Andreessen said.
Google’s executive chairman Eric Schmidt said Ms Mayer’s hiring was a “real win” for Yahoo, denying that she had become marginalised.