SUNNYVALE, Calif. — Motorola Mobility, the ailing cellphone maker that Google bought in May, told employees Sunday that it would lay off 20 percent of its workforce and close a third of its 94 offices worldwide.
The cuts are the first step in Google’s plan to reinvent Motorola, which has fallen far behind its biggest competitors, Apple and Samsung, and to shore up its Android mobile business and expand beyond search and software into the manufacture of hardware.
The turnaround effort will also be a referendum on the management of Larry Page, Google’s chief executive, whose boldest move has been the $12.5 billion acquisition.
Though Google bought Motorola partly because of its more than 17,000 patents, which can help defend against challenges to the Android operating system, it also planned to use Motorola to make its own, better smartphones and tablets.
One-third of the 4,000 jobs lost will be in the United States. The company plans to leave unprofitable markets, stop making low-end devices and focus on a few cellphones instead of dozens, Dennis Woodside, Motorola’s new chief executive, said in a rare interview.
‘‘We’re excited about the smartphone business,’’ said Woodside, who previously led Google’s sales and operations for the Americas. ‘‘The Google business is built on a wired model, and as the world moves to a pretty much completely wireless model over time, it’s really going to be important for Google to understand everything about the mobile consumer.’’
But some analysts wonder whether Google can succeed in the brutally competitive, low-margin cellphone business.
‘‘Ninety percent of the profits in the smartphone space are going to Apple and Samsung, and everyone else from Motorola to RIM to LG to Nokia are picking up the scraps of that 10 percent,’’ said Charlie Kindel, a former manager at Microsoft who writes about the mobile industry. ‘‘There’s no real sign that’s changing anytime soon.’’
It was not always this way. Motorola executives like to talk about its glory days. The company, started in 1928 in Chicago, unveiled the first commercial cellphone in 1973. By 2004, it looked as if Motorola could again lead the cellphone industry when it introduced the popular Razr.
But Apple and Samsung won consumers’ hearts with the more exciting iPhone and Galaxy phones. Motorola Mobility — which split last year from Motorola Solutions, the division that makes devices like police radios — lost $233 million in its first six weeks under Google. The phone business has been unprofitable for 14 of the last 16 quarters.
‘’It got left in the dust by the competition and kind of missed the smartphone transition,’’ said Charles S. Golvin, a mobile analyst at Forrester Research.
In addition to the coming cuts, Google has gutted Motorola management, letting go 40 percent of its vice presidents. It also hired new senior executives. It will shrink operations in Asia and India, and center research and development in Chicago, Sunnyvale and Beijing.
Woodside also plans to cut the number of devices Motorola makes from the 27 it introduced last year to just a few. He wants to make the company’s products cool again by loading them with things like sensors that recognize who is in a room based on their voices, cameras that take crisper photos and batteries that last for days.