Lee Kun-hee, chairman of Samsung Electronics, has died on Sunday at the age of 78. He was hospitalized since May 2014 after suffering a heart attack.

Lee, who transformed his father's small trading business into a global giant of consumer electronics, was the richest person in South Korea with a net worth of nearly $ 21 billion according to Forbes.

Under Lee's leadership, Samsung Electronics became one of the world's biggest tech firms. It become the world's largest producer of smartphones and memory chips with the firm's overall turnover today being equivalent to a fifth of South Korea's GDP.

"All of us at Samsung will cherish his memory and are grateful for the journey we shared with him," the firm said in a statement.

"Our deepest sympathies are with his family, relatives and those nearest. His legacy will be everlasting," it added.

Lee stepped down as Samsung chairman in 2008 after he was charged with tax evasion and embezzlement. He was handed a three-year suspended jail sentence for tax evasion but was given a presidential pardon in 2009. He returned as chairman of Samsung Group in 2010, but was left bedridden by the 2014 heart attack.

He died alongside his family, including his son and de facto company chief Lee Jae-Yong.