“My job is so top secret even I don’t know what I’m doing” is a jocular one-line saying that has been printed on many T-shirts and coffee mugs. The saying has been popular both in government and in business.
 
“I’m not kidding—my job is so secret even I don’t know what I’m doing” was printed in the Washington (DC) Post in 1951.
     
   
30 November 1951, Washington (DC) Post, “The District Line” by Bill Gold, pg. C10, col. 3:
OVERHEARD
“I’m not kidding—my job is so secret even I don’t know what I’m doing.”
 
Old Fulton NY Post Cards
9 September 1958, New York (NY) Post, “It Happened Last Night” by Earl Wilson, pg. M8, col. 3:
Quote says there’s an official at the Pentagon who has a sign on his desk announcing, “This Job Is So Secret I Don’t Know What I’m Doing.”
 
21 February 1962, Omaha (NE) World-Herald, “In Washington,” pg. 13, col. 2:
Secret
“My job is so secret,” joked a Pentagon wag the other night, “that I haven’t any idea what I’m doing.”
 
23 August 1969, Washington (DC) Post, “Interns Fill U.S. Job Role” by Ellen Hoffman, pg. B1:
“My job is so secret even I don’t now what I’m doing,” said the sign over the 16-year-old McKinley High School student’s work space.
(At the Goddard Space Flight Center.—ed.)
 
Google Books
The Battle of Britain, July-September 1940
By Marcel Jullian
New York, NY: Orion Press
1967
Pg. 29:
Today it hangs in the office of the Intelligence Branch of Fighter Command at Bentley Priory. It reads: “My job is so secret that I don’t know what I’m doing.” Clearly this card was not printed in 1940.
 
26 August 1971, The Morning News (Wilmington, DE), “Moyers bets on Dems in ‘72” by Hugh Cutler, pg. 50, col. 3:
He (Bill Moyers—ed.) joked that he realized that he had better leave LBJ’s administration when he found himself taking to heart the words of a plaque given him by the White House press corps: “My job is so secret I’m not permitted to know what I’m doing.”
   
10 June 1988, Arkansas Gazette (Little Rock, AR), “CIA director says his agency should be seen as responsive” by Lamar James, pg. 11A, col. 2:
... he (William Webster—ed.) said that when he took the job as CIA director “they gave me a button and it said, ‘My job is so secret even I don’t know what I’m doing.’”
 
Google Books
The Business Engineer
By Björn L. Rosvall
Stevenage: Peter Peregrinus
1996
Pg. 188:
I am sure you have heard of the development engineer with the sign on the wall behind him saying ‘my job is so secret that I don’t know what I’m doing’.
   
Google Groups: alt.games.final-fantasy
I JUST OVERCLOCKED MY COMPUTER!!!!!!!!!!!!!!!!1
Ash666 The Marionette
2/1/99
(...)
My job is so top secret ... I can’t even tell myself what I’m doing.
 
Google Groups: fido.belg.ned.systemen
DVD games
Dave Luyten
4/17/00
(...)
... My job is so top secret ... I can’t even tell myself what I’m doing.
 
Twitter
Manin De Polignan
‏@CyberManin
My job is so secret that I even don’t know what I’m doing…..  😊
7:52 PM - 29 Apr 2009
 
Twitter
Random Password
‏@randompassword
Tohf*ie4 #password - My job is so top secret ... I can’t even tell myself what I’m doing. My
10:09 AM - 4 May 2009
 
Twitter
Dana Bell
‏@dragonlots5
Button Saying: My job is so SECRET…even I don’t know what I’m doing. Found at a Con.
9:04 PM - 5 Jul 2009
 
Twitter
Adrian van zyl
‏@FunSailAd
my job is so top secret, even i don’t know what i’m doing most the time! - Patrick’s shirt
3:08 AM - 10 Nov 2009
 
Twitter
Cindy Jordan ⚡️
‏@Simply_CJ
My job is so top secret even I don’t know what I’m doing! 😊
Simply_CJ   😊
11:51 AM - 11 Nov 2009
   
Naked Capitalism
fresno dan
December 10, 2015 at 11:47 am
(...)
When I worked at the NSA, I used to say, “my job is so top secret, even I can’t know what I’m doing.”