American cartoonist and writer Ted Key (1912-2008) did a series of posters and one illustrated saying achieved popularity:
 
“Every job is a self-portrait of the person who did it.
Autograph your work with excellence!”
 
The saying has been frequently cited, but Key has rarely been credited.
 
   
Wikipedia: Ted Key
Ted Key, born Theodore Keyser (August 25, 1912 – May 3, 2008), was an American cartoonist and writer. He is best known as the creator of the cartoon panel Hazel, which was later the basis for a television series of the same name.
 
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Set of 3: 1965 Ted Key Poster No. 1,2, 3
No. 1:
It takes less work to do something right than to do it twice.
Be right, not sorry!
No. 2:
It’s a pleasure to be comfortably early.
Why spend your life racing the clock?
No. 3:
Every job is a self-portrait of the person who did it.
Autograph your work with excellence!
 
29 November 1967, Tripoli (IA) Leader, pg. 6, col. 6 ad:
THOUGHT OF THE WEEK
Every job is a self-portrait—Autograph your work with excellence.
Ray’s Clothiers & Cleaners
 
4 December 1969, Caribou County Sun (Soda Springs, ID), pg. 7, col. 5:
Every job is a self portrait of the person who did it. Autograph your work with excellence.
 
11 December 1969, San Marino (CA) Tribune, “Along the Drive,” pg. 1, col. 4:
Every job is a self portrait of the person who did it. Autograph your work with excellence.
 
23 October 1970, Ada (OK) Evening News, pg. 4, col. 7:
WORK—Every job is a self portrait of the person who did it…autograph your work with excellence!—The Christian Reader.
 
15 August 1971, Suburbanite Economist (Chicago, IL), sec. 2, pg. 5, col. 2:
Every job is a self portrait of the person who did it…autograph your work with excellence.
 
Google News Archive
26 March 1979, Youngstown (OH) Vindicator, “Develops Self Esteem” by Jane Lamb, pg. 21, col. 1:
Every job is a self portrait of the person who did it.
Autograph your work with excellence.
That motto, on an office wall at Goodwill Industries’ rehabilitation center, 2747 Belmont Ave., reflects the attitude that is helping handicapped people build the skills and self-esteem to make it in competitive industry.
 
Google News Archive
28 September 1979, Daytona Beach (FL) Morning Journal, “Model Makers Produce Dioramas, Exhibits” by Julius Kabash, pg. 4B, col. 3:
EBI (Exhibit Builders Inc.—ed.) President James C. Burkhalter says the key to his business is emblazoned across a placard on the shop wall that states: “Every job Is a self portrait of the person who did It. Autograph your work with excellence.”
 
Google Books
The Successful Volunteer Organization:
Getting started and getting results in nonprofit, charitable, grass roots, and community groups
By Joan Flanagan
Chicago, IL: Contemporary Books
1981
Pg. 179:
If you feel your patience ebbing, remember the words of Ted Key: ‘Every job is a self-portrait of the person who did it. Autograph your work with excellence.’
 
Google Books
How to Influence Children:
A Handbook of Practical Child Guidance Skills
By Charles E. Schaefer
Northvale, NJ: J. Aronson
1994
Pg. 160:
Every job is a self-portrait of the person who did it. Autograph your work with excellence.