Choi Gee Sung, 58

Samsung Electronics
President

Samsung has long favored managers with backgrounds in engineering. But Choi's background in design and marketing are a break from that tradition. After running the Korean company's mobile-phone business for two years, Choi was chosen in January to take on a bigger role because of his prowess in sales. While overseeing the mobile-phone unit, he ended his predecessor's policy of focusing on high-end phones to launch a suite of products that directly take on Nokia in lower-end segments. He increased Samsung's global market share by 5.1 percentage points from 2006 to 2008 to 16.7%, making it the world's second-largest handset maker and the only credible challenger to Nokia (NOK) on all fronts.

Choi has had a long string of successes on the job. After joining Samsung's trading arm in 1977, he had a stint as chief design officer and established Samsung's chip business in Europe in the 1980s. He's best known as a marketing expert. As president of Samsung's digital media business earlier this decade, he rolled out a string of innovative products. In the process, he guided Samsung past Sony to become the world's No. 1 TV brand in 2006.

Now many view him as the leading contender for CEO. His immediate goal: significantly narrow the game with Nokia in mobile phones. If Choi does that, he'll likely get the top job.

--by Moon Ihlwan