“Do not let what you cannot do interfere with what you can do” is what UCLA basketball coach John Wooden (1810-2010) said in his book, They Call Me Coach (1972). It’s not known when Wooden first said this; he produced many bits of philosophy used in sports (and elsewhere in life) that have been called “Woodenisms.”
 
“Do not let what you cannot do get in the way of what you can do” was printed in a 1971 issue of The Presbyterian Journal.
 
 
Wikipedia: John Wooden
John Robert Wooden (October 14, 1910 – June 4, 2010) was an American basketball player and coach. Nicknamed the “Wizard of Westwood”, he won ten NCAA national championships in a 12-year period — seven in a row — as head coach at UCLA, an unprecedented feat. Within this period, his teams won a record 88 consecutive games. He was named national coach of the year six times.
     
Google Books
The Presbyterian Journal
Volume 30
1971
Pg. 13:
Do not let what you cannot do get in the way of what you can do. Pick every chance to make your life an effective influence.
 
Google Books
They Call Me Coach
By John Wooden with Jack Tobin
Waco, TX: Word Books
1972
Pg. 56:
Do not let what you cannot do interfere with what you can do.
 
14 February 1975, Daily Inter Lake (Kalispell, MT), “Time Out” by Rev. Everett L. Cecil, pg. 9, col. 2:
John Wooden writes: “Do not let what you cannot do interfere with what you can do.”
 
Google Books
Aquatic recreation for the blind:
A project of Bureau of Education for the Handicapped, Division of Innovation and Development, U.S. Office of Education, Department of Health, Education and Welfare
By Harry C Cordellos; Information and Research Utilization Center in Physical Education and Recreation for the Handicapped.; United States. Bureau of Education for the Handicapped. Division of Innovation and Development.; American Alliance for Health, Physical Education, and Recreation.
Washington, DC: Physical Education and Recreation for the Handicapped, Information and Research Utilization Center
1976
Pg. 33:
Do not let what you cannot do interfere with what you can do.
John Wooden
 
11 July 1976, Winona (MN) Daily News, “Inflation, vandalism: twin villains appear at park talks” by Terry Bormann, pg. 3A, col. 4:
‘Do not let what you cannot do interfere with what you can do,” Welch concluded.
(Robert Welch, city park recreation director—ed.)
 
18 May 1977, Salina (KS) Journal, “Bryce Young putting back much more than he took out” by Gary Isaacson, pg. 19, col. 2:
He (Bryce Young—ed.) has a motto that is appliable to the situation.
 
“Don’t let what you can’t do keep you from being successful at what you can do.”
     
Google Books
The Coach
By Ralph J. Sabock
Philadelphia, PA: Saunders
1979
Pg. 128:
Do not let what you cannot do interfere with what you can do. The good coach will take what talent is there and do the best possible job with it, and not spend time in the futility of looking at a squad and saying, “If only we had this or that.”
 
Google News Archive
13 October 1983, Regina (Saskatchewan) Leader-Post, “Tragic event won’t slow her down,” pg. C8, col. 2:
“You shouldn’t let what you can’t do interfere with what you can,” she says.
(Margaret Lawson, a University of Toronto student—ed.)
 
ESPN.com
Originally Published: June 4, 2010
The Wizard’s wisdom: ‘Woodenisms’
By ESPN.com staff
The life lessons taught by John Wooden have become legend. Here’s a collection of some of the greatest “Woodenisms.”
(...)
“Do not let what you cannot do interfere with what you can do.”