“No brain, no gain”—a rhyme similar to “No pain, no gain”— is an education saying that has been printed on many images. “No brain, no gain” was printed in newspapers in 1987, 1988 and 1989.
 
“No brain, no gain. Stay in school” is a longer saying that has been printed on many images. Posters of this saying with basketball superstar Michael Jordan—the photo appears to be of Jordan in a library, during his school days—has been cited in print since at least 1992.
 
         
25 November 1987, The Globe and Mail (Toronto, ON), pg. D1, col. 2:
CFL-killer: a Hal of an idea
No brain, no gain for Plato of pigskin
TRENT FRAYNE
 
1 May 1988, Washington (DC) Post, pg. C1, col. 4:
The Rise of Smart Chic
No Brain, No Gain—Intellect is Back in Vogue
(...)
Anyway, the new fad. Could it be: thinking?
 
7 July 1989, State-Times (Baton Rouge, LA), “Muscles bringing Cockerham fame” by George Morris, pg. 3-D, col. 2:
“It’s not something you can do if you’re just a big, dumb jock,” said Beth Herbert, who runs the Cypress Gym with her husband, Al. It used to be, ‘No pain, no gain.’ Now it’s, “No brain, no gain.’ You have to be fairly intelligent about diet and training.”
 
12 February 1992, Daily Press (Newport News, VA), “Center of community filled with hope” by Javler Solano, pg. C6, col. 3:
That kind of thinking is perhaps what separates recreation centers from private clubs. Private clubs don’t have Youth Job Fairs and Just Say No Fests. Their lobbies don’t have Michael Jordan “No Brain No Gain - Stay In School” posters.
       
Google Groups: alt.cyberpunk
present state of technology
Long, Joseph Louis
8/21/92
(...)
“No brain… No pain!”
“No pain… No gain!”
= “No brain… No gain!”
     
IMDb.com (The Internet Movie Database)
ER (1994–2009)
No Brain, No Gain
TV-14 | 1h | Drama, Romance | Episode aired 14 November 1996
Season 3 | Episode 7
Encouraged by Carol, Mark finally asks Susan out. Benton tries to save a boy, despite the fact Doug thinks he’s brain dead.
Director: David Nutter
Writers: Michael Crichton (created by), Paul Manning
 
Google Books
Sport and Postmodern Times
Edited by Geneviève Rail
Albany, NY: State University of New York Press
1998
Pg. 209:
Coke also used Jordan in a similar role in their “No Brain No Gain: Stay in School” campaign, as did Nike when recently re-uniting him with Mars Blackmon in a schoolroom setting in which after a rather intense discussion about the principles of gravity, the two friends exclaim “Don’t Be Stupid. Stay in School.”
 
Twitter
Miss-Nikki Bee
@MissNikkiBee
No brain. No gain . . . Stay in school.
12:39 AM - 5 May 2011
 
Twitter
∞
@SoulAmayzin
No Brain no gain. Stay in school! lol
2:11 AM - 6 May 2011
 
Twitter
MiMS
‏@_boyidk
No brain no gain. Stay in school.
11:48 AM - 6 May 2011
 
Twitter
Coach Potato
@CoachPotato
No Brain No Gain: Vintage Michael Jordan ‘Stay In School’ PSA http://tinyurl.com/3hlfsmg
4:05 PM - 7 May 2011
 
Twitter
The Spew Network
@TheSpewNetwork
No Brain No Gain: Vintage Michael Jordan ‘Stay In School’ PSA http://bit.ly/jOvGJH
6:25 PM - 7 May 2011
   
Customer Think
How to Make Freelance Contact Center Agents Successful
Anand Subramaniam - June 30, 2018
(...)
Tips for Success
(...)
1. Take a knowledge-first approach. “No brain, no gain” is the 21st Century version of the idiom “no pain, no gain.” In fact, lack and consistency of agent knowledge is the biggest pain point in customer service, according to a recent eGain-Forrester survey of 5,000 consumers in the US. So focus first on knowledge, or the biggest customer pain point could get amplified by the freelance approach!