NFL Players Association executive director Gene Upshaw died Wednesday night at his home in Lake Tahoe, Neb., at the age of 63.
Upshaw learned he had pancreatic cancer on Sunday.
He is survived by his wife Terri and three sons, Eugene, Justin and Daniel.
"We are deeply saddened and shocked by the sudden and unexpected death of our leader," said a statement on the NFLPA website.
Upshaw, NFLPA chief since 1983, is credited with negotiating record-setting salaries for current NFL players and fhas helped in negotiating labor peace with owner during the era of the collective bargaining agreement. Recently, he drew criticism from existing players and former players over how he did his job.