Nissan (NSANY) , one of the world's largest carmakers, completed its acquisition of a ¥237 billion ($2.3 billion) stake in Mitsubishi Motors Thursday, paving the way for its highly-regarded CEO to assume the role of chairman.

Nissan paid ¥468.52 a share for about 34% of Mitsubishi stock and will be unable to sell the shares for three years outside group companies, which include Nissan affiliate Renault  (RNLSY) .

A Renault-Nissan-Mitsubishi alliance would create the world's fourth-largest automotive group, behind Toyota (TM) - Get Report , Volkswagen (VLKAY) and General Motors. (GM) - Get Report

Mitsubishi shares closed 2.68% up at ¥536 and Nissan gained 0.75% in Tokyo. Renault was recently up 0.01% to €77.44 in Paris. 

Nissan said earlier this spring that it would buy a stake in Mitsubishi after the company became embroiled in an emissions scandal. Mitsubishi shares have fallen 40% since the it came to light that Mitsubishi falsified data on the fuel economy of four models, including two produced for Nissan.

CEO Carlos Ghosn will take up the chairman role on December 14 as he attempts to turn around the ailing car maker. Osamu Masuko will step down as Mitsubushi Motors chairman but stay on as president.

"I asked Masuko to stay on as president. He wanted to resign to take responsibility for the mileage scandal," Ghosn said during a press conference Thursday. 

Mitsubishi is expected to incur a loss of ¥240 billion in the year ending in March 2017 due to the scandal. 

Ghosn, who is also the CEO of  Renault, was once dubbed "Le Cost Killer" by the French media and became the subject of superhero comic series in Japan. He has been credited with turning around both Renault and Nissan.

The 62-year old executive is also the CEO and chairman of the Renault-Nissan Alliance, a role he's held since 2001 after a strategic cross-shareholding agreement between the two companies. The alliance is the world's leading manufacturer of plug-in electric vehicle and producer of the world's top selling electric car the Nissan Leaf. It sold 8.5 million vehicles last year.

Ghosn joined Renault from Michelin in 1996 as executive vice president in charge of purchasing, advanced research, engineering and development, powertrain operation and manufacturing. His radical restructure returned Renault to profitability in 1997. He become president and CEO in 2005, and chairman and CEO in 2008.

Along with keeping his responsibilities at Renault, Ghosn became COO at Nissan after the French carmaker bought a 36.8% stake in Nissan. He was named president and CEO in June 2001 and added the chairman role in 2008.

In 1999, Ghosn announced the Nissan Revival Plan, which called for a return to profitability in the fiscal year 2000, a profit margin of more than 4.5%  of sales by the end of fiscal year 2002 and a 50% reduction in the level of debt by the end of the 2002 fiscal year. The plan that was successful.

He also spearheaded a structural and corporate-culture changes at the company

Ghosn became a well-known and popular figure in Japan after he returned Nissan to profitability. His life has even been turned into a superhero comic book series in Japan, called The True Story of Carlos Ghosn. He also has a bento box named after him in some Tokyo restaurants.