Who said that "Courage is grace under pressure."?

The phrase "Courage is grace under pressure" was used by Ernest Hemingway. For him and those who believe him, it means you are not falling apart and becoming hysterical. You are nervous but you are acting graceful in holding your composure. So it was Ernest Hemingway who clearly defined the word "courage" as "grace under pressure".

When describing someone he considered to be a hero, Hemingway wrote that his hero is:

"... a man who lives correctly, following the ideals of honor, courage and endurance in a world that is sometimes chaotic, often stressful, and always painful."

When in bad situations and under conditions of extreme pressure, the brave man will handle the required events and duties without any shortage of braveness (courage) and self-confidence. He will not crumble; he will rise up and face the crisis at hand. He will find an answer.