What made Ernest Hemingway one of the most popular American writers of his time ?possible examples from his life ?

The soul of the journalist never left Ernest Hemingway. 
Whether he wrote of upper Michigan where he grew up or the conflicts of war and the
heart and the soul where Hemingway had lain himself, he chose to report rather than to
interpret.  A perceptive traveler through life, Hemingway always left an opening in his
minimalist prose for the reader to find the deeper meaning for himself, participating in
the realism of many of his narratives.

The presenter of the
Nobel Prize for Literature said of Hemingway,

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With masterly skill [Hemingway] reproduces all
the nuances of the spoken word, as well as those pauses in which thought stands still
and the nervous mechanism is thrown out of gear. It may sometimes sound like small talk,
but it is not trivial when one gets to know his method.  He prefers to leave the work of
psychological reflection to his readers and this freedom is of great benefit to him in
spontaneous
observation.

Harold Bloom,
the renowned scholar, pronounced Hemingway "a minor novelist" with a "major style." 
Another critic said of Hemingway that he has changed the rhythms of the way both his own
and the next generation would speak and write and think.   Hemingway became a
trendsetter.  His stories portray the disillusioned man, the aimless, the dehumanized
soldier who still hurts.  Hemingway became the voice for a generation--the "lost
genreation"--that saw a world war, financial corruption, and immorality.  Having written
about that which he has experienced, Hemingway's narratives contain a reality that draws
in the fisherman to The Old Man and the Sea, the soldier to
A Farewell to Arms and For Whom the Bell Tolls, the outdoorsman in
the Nick Adams stories, and the jaded and directionless in The Sun Also
Rises.