Lee has faced a series of legal troubles in the past two years
The former boss of Samsung Electronics, who was convicted of tax evasion and later given a presidential pardon, has returned to head the company.
Lee Kun-hee headed Samsung for two decades before stepping down in April 2008, three months before being handed a three-year suspended sentence.
Analysts said Mr Lee's return was good news for the electronics giant.
Mr Lee, 68, whose father founded Samsung, is seen as one of the South Korea's most prominent businessman.
He is also one of the country's richest men.
Mr Lee received a special presidential pardon in December last year, so that he could return to the International Olympics Committee and help South Korea's bid to host the 2018 Winter Olympics.
Since his pardon, expectations of a return to Samsung have been growing.
"Lee's return removes what had been an uncertainty for Samsung Group," said Park Yun-chae at Kiwoom Securities.
"Under the ownership management, a founding family member offers long-term visions that are critical to the group's direction. [Mr Lee] is expected to help Samsung find its long-term goals and plans."
However, questions were raised about re-appointing a convicted tax evader, albeit one who had been pardoned, to run the company.
"This sort of decision shows that Samsung is very closed off to outside opinion on how the company should be run," said Kim Sang-jo, associate professor of economics at Hamsung University.
"Its decisions are being made by a very small group of people encased in its thick walls."