Detroit Lions Football Hall of Fame offensive guard Lou Creekmur (1927-2009) was 30 years old in 1957 when he said:
 
“When you win. you’re an old pro; when you lose, you’re an old man.”
 
New York Giants quarterback Charlie Conerly (1921-1996) had just turned 40 years old in 1961 when he also said, “When you win, you’re an old pro. When you lose, you’re an old man.” Conerly is usually credited for the saying, but Creekmur said it first.
 
 
Wikipedia: Lou Creekmur
Louis Creekmur (January 22, 1927 – July 5, 2009) was an NFL left offensive tackle/guard for the Detroit Lions from 1950-59. He was also used as a defensive lineman in critical situations. In 1996, he was enshrined in the Pro Football Hall of Fame.
 
Creekmur played football in an era in which protective equipment - especially helmets - were nowhere as sophisticated as they are today. During his high school and early pro years, anyone who wore a face mask was considered a “sissy.” As a result, Lou Creekmur’s nose has been broken and reset some 13 times. Like many players of the 1940s and 1950s, he has that distinctive “flat nose” look that comes about from most of the cartilage being gone.
 
Apart from the broken noses, Creekmur is remarkable in that in ten full seasons he never missed a game.
 
Google News Archive
30 December 1957, Milwaukee (WI) Sentinel, “Detroiters Never Had a Chance to Relax: Lions Credit Uphill Season” (AP), pt. 2, pg. 3, col. 5:
Creekmur, who often has said that “when you win. you’re an old pro; when you lose, you’re an old man,” said in reviewing Sunday’s triumph: ...
(Lou Creekmur, veteran offensive guard for the Detroit Lions—ed.)
 
Google News Archive
28 January 1958, Park City Daily News (Bowling Green, KY),  “So They Say,” pg. 5, col. 3:
When you win, you’re an old pro; when you lose, you’re an old man.
—Lou Creekmur, veteran guard of National Football League champion Detroit Lions.
 
28 October 1961, New York (NY) Times, “Conerly Tells How to Call Plays; Quarterback, 40, Says Gridiron Is Like a Chessboard, Experience Helpful in Making Quick Shift in Plans” by Robert L. Teague, pg. 16:
As viewed by Charlie Conerly, a football field is like a king-sized chessboard and his job as quarterback for the New York Giants is to advance the attacking pieces against the most vulnerable segment of the defense.
(...)
When reminded of this turnabout yesterday, Charlie said: “When you win, you’re an old pro. When you lose, you’re an old man.”
 
Time magazine
People: Nov. 3, 1961
Friday, Nov. 03, 1961
Between relentless red-dogs on the field and yapping jackals in the stands, 14 lacerating seasons in the National Football League had made a philosopher of the New York Giants’ golden-armed Quarterback Charlie Conerly, 40. Congratulated on a brilliant performance against the Los Angeles Rams that temporarily silenced armchair coaches who argue that he should be benched because of his age, Conerly thoughtfully observed: “When you win, you’re an old pro. When you lose, you’re an old man.”
 
Google Books
Old Age Is Always 15 Years Older Than I Am
By Randy Voorhees
Kansas City, MO: Andrews McMeel Publishing
2001
Pg. 197:
When you win, you’ re an old pro. When you lose you’re an old man. — Charlie Conerly, U.S. professional football player.
 
Google Books
Tweet This Book:
The 1,400 Greatest Quotes of All Time in 140 Characters Or Less
By Sayre Van Young and Marin Van Young
Berkeley, CA: Ulysses Press: Distributed by Publishers Group West
2011
Pg. 23:
When you win, you’re an old pro. When you lose, you’re an old man.
Charlie Conerly