SEOUL—The head of Samsung Electronics’ smartphone and consumer electronics business died from cardiac arrest on Tuesday, jolting the South Korean technology giant during a business slide that leaders have called a crisis.

Han, who was credited with elevating the company’s television business, died at a hospital after being treated for cardiac arrest.

Han Jong-Hee, the co-chief executive of Samsung Electronics and a nearly four-decade veteran of the South Korean consumer technology giant, died on Tuesday. Mr. Han, who was 63, suffered a sudden heart attack, according to a company spokeswoman.