"Don’t watch the clock; do what it does Keep going!” has been printed on many posters, with credit usually given to Brooklyn-born humorist Sam Levenson (1911-1980). Levenson included the saying in his book, You Don’t Have to Be in Who’s Who to Know What’s What (1979).
Wikipedia: Sam Levenson
Sam Levenson (December 28, 1911 – August 27, 1980) was an American humorist, writer, teacher, television host, and journalist.
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You don’t have to be in Who’s who to know what’s what
Author: Sam Levenson
Publisher: New York : Simon & Schuster, ©1979.
Edition/Format: Print book : English
Words of Wisdom
Edited by William Safire and Leonard Safir
New York, NY: Simon & Schuster
Don’t watch the clock; do what it does. Keep going. — Sam Levenson
10 January 2002, Daily Republican Register (Mt. Carmel, IL), pg. 1, col. 4:
MUSINGS ON THE WABASH
Don’t watch the clock. Do what it does. Keep going. — Sam Levenson
17 April 2003, The Advocate (Stamford, CT), “Daily Bridge Club” by Frank Stewart, pg. C6, col. 1:
“Don’t watch the clock. Do what it does. Keep going!”—Sam Levenson.
Better Resume Svc.
Do not watch the clock. Do what it does. Keep going. - Sam Levenson #quote
12:33 PM - 21 Mar 2015