Benjamin Smith made the pledge in a video message to staff as he officially took up his new position as chief executive at the French-Dutch airline.
His fixed salary is 900,000 euros ($1.0 million) a year, but his total compensation can reach as high as 4.25 million if performance targets are met.
The pay package was roundly criticised by unions, as it is more than three times the amount paid to Smith's French predecessor, who quit in May after gambling his job on getting staff to accept a pay deal that was rejected in a company-wide vote.
“I have already made a personal investment by moving with my family to France,” Smith says in the video, according to a French transcript obtained by AFP.
“Today I have decided to make another investment by investing half my fixed salary in Air France-KLM's share capital,” he said.
“It's a way of demonstrating my confidence in our future success,” he added. “I'm investing because I believe we can win in our market and become number one, but I also want to show my committment.”
The airline has been battling stiff competition from low-cost rivals while also facing aggressive moves by Gulf carriers into Europe.
And French pilots and other workers carried out a series of costly strikes earlier this year after management rebuffed wage demands, leading to losses the airline estimated at 335 million euros.
Earlier this month Dutch pilots reached a deal on wages and working conditions with KLM management after threatening to walk off the jobs.
Unions have also bristled at bringing in a foreigner — Smith is Canadian — to run a company in which the French government still owns a 14.3 percent stake.
But the government has defended his appointment, citing a 19-year career at Air Canada, where he led labour negotiations ahead of the launch of a low-cost subsidiary.
The 47-year-old, who was chief operating officer at Air Canada, is also credited with turning the airline around in the wake of the 2008 global economic crisis.
“We sought out one of the top professionals in the world,” Transport Minister Elisabeth Borne said on French television on Monday.
“What is urgent now is a strategic plan,” she stressed. “Obviously he will be meeting with unions and I hope everyone is going to contribute to this development project for Air France.”
She declined to be drawn out on whether the government planned to sell any of its shares to finance national development projects.