Haynes was found dead Friday after family and friends could not reach him by phone, The Philadelphia Inquirer reported. The Medical Examiner's Office said the cause of death had not yet been determined.
Haynes is credited with putting together and overseeing a team of Pulitzer Prize-winning photographers at the Inquirer in the 1970s and '80s. Two staff photographers won Pulitzers and a third prize went to the staff.
The Inquirer hired Haynes away from The New York Times in 1974. He also had previously worked for United Press International.
"Almost overnight, he brought the paper into modern photojournalism," Gene Roberts, the editor who hired him at the Philadelphia newspaper said.
Inquirer photography Clem Murray said Haynes could "find the picture within the picture," cropping it to provide its greatest impact.
"Gary was a big personality with big ideas," Murray said. "He pushed us to be creative and do whatever it took to capture 'The Moment.'"
The Salina, Kan., native got his first taste of photography while in the Army. He was hired by UPI in Detroit in 1958.
His career included covering the civil rights movement, anti-Vietnam War demonstrations, space launches, Olympic Games, the World Series and presidential campaigns.
He also compiled the 2006 book "Picture This!: The Inside Story and Classic Photos of UPI Newspictures."
He is survived by his son Philip and daughters Stephanie and Emily.
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