Koh, who studied science and technology policy at the University of Sussex in the U.K., has served diverse R&D positions at Samsung since joining the group in 1981.

Over the past year, he led the development of the latest Galaxy S6 and Galaxy Note 5 phones. He also has software expertise, leading key projects such as the Samsung Pay mobile payment system and the KNOX mobile security platform.

Shin, who has been affectionately called “Mr. Galaxy,” oversaw the launches of Galaxy and other key handsets over the past three years.

Largely buoyed by the success of the Galaxy brand, he was named the highest-paid corporate executive in Korea last year with a combined compensation of 12 billion won ($10 million). But his position was on shaky ground in recent quarters due to lukewarm sales of the latest Galaxy S6 phones.

“Shin may have retained his post (as CEO), but the top management is signaling that they may replace him soon,” said Kwon Sung-ryul, an analyst at Dongbu Investment and Securities.

He predicted the new head Koh could bring a fresh opportunity to shake up the company’s smartphone strategy overall next year.

Samsung said that another co-CEO Yoon Boo-keun, home appliances business division chief, will also hand over control of the digital appliances business division to a “younger” successor who is likely to be named later this week.

While the two co-CEOs will be stepping back from day-to-day operations to serve advisory roles, the remaining chief executive Kwon Oh-hyun, head of the chip-making division, will continue his job beefing up the lucrative chip businesses.

Keen attention was paid to Tuesday’s management reshuffle because it was the first one carried out under the leadership of Samsung Electronics vice chairman and the group’s heir apparent Lee Jae-yong.

“No drastic change has been made as the big three (the three co-CEOs) have been retained,” said Lee Seung-woo, an analyst at IBK Investment & Securities. “Samsung chose continuity over fresh blood.”

Samsung Group on Tuesday announced 15 transfers and appointments, including six promotions to president. With eight presidents being sacked, the total number of Samsung presidents across its affiliates will be 52 next year, down from 53 this year and 60 in 2014.

The group plans to announce the list of executive promotions on Friday. Amid a sense of crisis, the figure is expected to be the lowest at about 300. There are about 2,000 executives throughout all Samsung affiliates.

Among the leadership transfers, reactions were especially mixed about the transfer of Samsung SDS president and CEO Jun Dong-soo to president of Samsung Electronics’ health and medical equipment business division.

Some industry watchers said he would play a bigger role in biotechnology, one of the company’s new growth engine businesses, while others called his transfer more a relegation rather than a promotion.

Other key figures promoted included Chung Yoo-sung, executive adviser at Samsung Economic Research Institute who will replace Jun as president and head of the IT solution unit; and Hong Won-pyo, president and head of the global marketing office who has been named president of Samsung SDS’ solutions business division.

By Lee Ji-yoon and Kim Young-won (jylee@heraldcorp.com) (wone0102@heraldcorp.com)