Young Winthrop was a third-generation member of the Rockefeller family. The 3 years he spent in the oil fields followed his expulsion from Yale University as a result of “misbehavior”.
He enlisted in the Army as a private during WW II and earned a Bronze Star with Oak Leaf Clusters and a Purple Heart for his actions aboard the troopship USS Henrico, after a kamikaze attack during the invasion of Okinawa. 
Winthrop Rockefeller moved to Arkansas in 1953 and served as the state’s 37th governor (1967—1971).
It appears that a little hard work never hurt anybody, even the rich folks among us.
(Click on image to enlarge)
Source: San Bernardino Sun Newspaper, January 19, 1937 via California Digital Newspaper Collection, Center for Bibliographic Studies and Research, University of California, Riverside