“Don’t/Never put the/your key to happiness in someone else’s pocket” is an inspirational saying that has been printed on many images. “‘Don’t put the key to your happiness in someone else’s pocket.’-Swami Chinmayananda” was posted on the newsgroup misc.kids on May 11, 1992.
 
Swami Chinmayananda Saraswati (1916-1993) has been frequently credited with the saying, but it’s not certain when it was first made.
         
   
Wikipedia: Chinmayananda Saraswati
Swami Chinmayananda Saraswati (born Balakrishna Menon; 8 May 1916 – 3 August 1993) was a Hindu spiritual leader and teacher who inspired the formation of Chinmaya Mission, a worldwide nonprofit organisation, to spread the knowledge of Advaita Vedanta, the nondual system of thought found in the Upanishads, which epitomise the philosophical teachings of the Vedas.
     
Google Groups: misc.kids
Travelling to Disneyland in LA and San Diego
Suneeta Aggarwal (415)617-2428
5/11/92
(...)
“Don’t put the key to your happiness in someone else’s pocket.”
-Swami Chinmayananda
 
OCLC WorldCat record   
Ever-Green messages: Quotes
Author: Chinmayananda, Swami; Central Chinmaya Mission Trust,
Publisher: Bombay : Central Chinmaya Mission Trust, 1995.
Pg. ?:
Don’t put the key to your happiness in someone else’s pocket.
 
Google Books
Gratitude:
Words of Wisdom to Guide, Influence, Inspire and Share
By Lenore Skomal, Lifelesson Foundation
Kennebunkport, ME: Cider Mill Press Book Publishers
2006
Pg. ?:
Don’t put the key to your happiness in someone else’s pocket.- - Swami Chinmayanandaji
 
October-December 2006, Hinduism Today, “Quotes & Quips” by Swami Chinmayananda, pg. 14:
Don’t put the key to your happiness in someone else’s pocket.
 
Twitter
bhogi gondalia‏
@123beegee
“Don’t put the key to your happiness in someone else’s pocket but into your own.”
2:04 AM - 11 Apr 2009
 
Twitter
Vijayashankar‏
@vjshankar
“Don’t put the key to your happiness in someone else’s pocket but into your own.” @_robin_sharma @tonyrobbins
10:41 AM - 11 Apr 2009
 
Twitter
Michael Scott Hand‏
@Himmathand
“Don’t put the key to your happiness in someone else’s pocket.” — Swami Chinmayananda (via @HinduismToday)
9:37 PM - 28 Jan 2010
 
Google Books
Heaven? or Hell? A Soul’s Choice
By J. L. Weaversmith
Bloomington, IN: WestBow Press
2015
Pg. 79:
“Never put the key to your happiness in someone else’s pocket”. Tom Ziglar
 
Google Books
Moving Forward:
Overcoming the Habits, Hangups, and Mishaps That Hold You Back
By John Siebeling
Grand Rapids, MI: Baker Books
2016
Pg. ?:
But we can’t ever put the responsibility for our happiness, joy, or health on someone else. You might have heard it said this way: “Don’t put the key to your happiness in someone else’s pocket.” It’s not fair to you, and it’s not fair to them.