The 55-year-old shooter walked into the North Texas store and fatally shot a 59-year-old store associate of the Walmart in the store's garden center, Kaufman Police spokesman Ed Black said.
It was initially reported that the gunman turned the gun on himself and died. However, later police clarified that the gunman survived and was taken to a hospital.
The two men had an ongoing dispute but no other details were available as to what prompted the shooting in Kaufman, Black said.
The store employees were allowed to return to the store, but it was closed for shoppers.
A Wal-Mart spokeswoman said in a statement, "We're deeply saddened by the tragic situation that occurred in our store today. We're assisting law enforcement however we can and our thoughts are with the families and our associates at this time.