Wal-Mart Stores Inc
Khasis confirmed his appointment but declined to give any details about his intended role at the world's biggest retailer.
Wal-Mart has been talking about entering the Russian market for years but appeared to have given up in December when it closed its Moscow office due to a lack of acquisition opportunities.
We still believe the Russia market has promise and we'll continue, as we do in markets all over the world, to watch for the right market-entry opportunity, the spokeswoman said.
Khasis, 45, built up X5 through acquisitions into a Russian market leader with $11 billion in annual sales during five years at the helm. < ID:nLDE7292CD>
He left the company in March, saying he would pursue other opportunities, but remains the chairman of the Association of Retail Companies (ACORT) - the Russian retail industry lobby.
They (Wal-Mart) have always said Russia is too big a market to ignore and at some point would come back ... Khasis knows how to go about things in Russia, he has connections, he understands how the local market works, said Mikhail Terentiev, retail analyst at Otkrite in Moscow.
He added, however, that a successful acquisition of a Russian company could still take years.
International retailers have long been trying to break into the Russian market to take advantage of steadily rising consumer spending in the wake of the financial crisis, but many have struggled to find a foothold.
Russian retail sales were up 5.6 percent year on year in July, the same rate as the previous month, while X5 and rival Magnit
The Wal-Mart spokeswoman said Khasis would be based at the company's headquarters in Bentonville, Arkansas, reporting to Walmart International's chief executive, Doug McMillon.
He will be responsible for integration, purchase leverage and innovation teams, she added.
Wal-Mart's total sales were $418.95 billion last year, with most of that coming from the United States. Walmart International had sales of $109.23 billion in the latest fiscal year, which ended on January 31.
(Additional reporting by Maria Pls and John Bowker Writing by John Bowker and Maria Kiselyova; Editing by)