This is attributed to Truman in some sources, but a similar saying is recorded as early as 1909 https://books.google.com/books?id=bidJAAAAIAAJ&dq=how%20much%20%22care%20who%20gets%20the%20credit%22&pg=PA26#v=onepage&q=how%20much%20%22care%20who%20gets%20the%20credit%22&f=false.
Misattributed
“It is amazing how much can be accomplished if no one cares who gets the credit.”
“it's amazing what you can get used to.”
“It's amazing what one can accomplish when one doesn't know what one can't do.”
“There is no limit to what a man can do or where he can go if he doesn't mind who gets the credit.”
Reagan reportedly displayed a plaque with this proverbial aphorism on his Oval Office desk (Michael Reagan, The New Reagan Revolution (2010), p. 177). Harry S. Truman is reported to have repeated versions of the aphorism on several occasions. This exact wording was in wide circulation in the 1960s, and the earliest known variant has been attributed to Benjamin Jowett (1817–1893).
Misattributed
From a letter to his son, as quoted in Harold Nicolson, Dwight Morrow (1935), p. 52
1974 speech, in Voices of Multicultural America: Notable Speeches Delivered by African, Asian, Hispanic and Native Americans, 1790-1995 by Deborah Gillan Straub
“Want more credit for all you do and who you are? Be the one who gives credit to others.”
