“The most important ingredient in the formula of success is knowing how to get along with people”

“The most important single ingredient in the formula of success is knowing how to get along with people” is a line that has been credited to Theodore Roosevelt (1858-1919). Dale Carnegie (1888-1955) wrote in newspaper columns in 1939 and 1942:
 
“The same theory was practiced by President Theodore Roosevelt who used to say: ‘The most important single ingredient in the formula of success is the knack of getting along with people.’”
 
The quote has not been found in a citation during Roosevelt’s lifetime.
 
 
5 November 1939, Joplin (MO) Globe, Dale Carnegie column, pg. 6A, col. 3:
The same theory was practiced by President Theodore Roosevelt who used to say: “The most important single ingredient in the formula of success is the knack of getting along with people.”
     
Old Fulton NY Post Cards
25 June 1942, Rogersville (TN) Review, Dale Carnegie column, pg. 2, col. 4:
The same theory was practiced by President Theodore Roosevelt who used to say: “The most important single ingredient in the formula of success is the knack of getting along with people.”
 
23 November 1954, Tyrone (PA) Daily Herald, pg. 7, col. 1:
Words of the Wise
The most important single ingredient in the formula of success is the knack of getting along with people.
—(Theodore Roosevelt)

4 April 1958, Arkansas State Press (Little Rock, AR), pg. 10, col. 3:
Though For The Week: The most important single ingredient in the formula of success is know how to get along well with people.”
     
16 September 1965, Springfield (MA) Union, “Today in History” (AP), pg. 2, col. 2:
Thought for today: The most important single ingredient in the formula of success is knowing how to get along with people—Theodore Roosevelt.
 
Google Books
Your Attitude:
Key to Success
By John Maxwell
San Bernardino, CA: Here’s Life Publishers
1984
Pg. 25:
That is why Teddy Roosevelt said, “The most important single ingredient to the formula of success is knowing how to get along with people.”
 
5 December 1988, Mobile (AL) Register, “Today in history” by The Associated Press, pg. 8-B, col. 3:
Thought for today: “The most important single ingredient in the formula of success is the knack of getting along with people.”—President Theodore Roosevelt (1858-1919).
 
Google Books
Mr. Littlejohn’s Secrets to a Lifetime of Success
By Pat Williams with Jim Denney
Grand Rapids, MI: F.H. Revell
2000
Pg. 82:
Theodore Roosevelt showed enormous wisdom when he observed, “The most important single ingredient in the formula of success is knowing how to get along with people.”
 
Google Books
Motivational, Inspirational and Success Quotes - To Get Motivated Every Day
By Elijah Bartini
LunaBulle
2013
Pg. ?:
493
The most important single ingredient in the formula of success is knowing how to get along with people.
Theodore Roosevelt