This "old soldier" was a general at age 38; in 1930 at age 50, he was Chief of Staff of the U.S. Army
He was Chief of Staff of the United States Army during the 
1930s and played a prominent role in the Pacific theater ..... By 1930, MacArthur 
was still, at age 50, the youngest of the U.S. Army's major generals, and the best 
known.