There are many theories as to whom Richard Cory refers. Some have suggested that two individuals who lived in Gardiner, Maine (Robinson’s home town) may have been the models for the character: Sedgewick Plummer; and Frank Anne. Some have even proposed that it was Robinson’s brother, who had squandered his part of the family fortune and fallen on hard times in the 1890’s.
But my instinct says that Richard is actually Robinson himself, who may have been feeling down when the poem was written. Perhaps he was contemplating suicide, but he presented it as someone else, because he recognized that no one would understand why. The ‘story’ is written out in just sixteen lines (such is the power of poetry) and the point-of-view is from the “common man”. The moral of the story is that money doesn’t bring happiness, even though everyone thinks it does.
Paul Simon brought the story forward into the 1960’s with his reworking of the poem into a Simon & Garfunkel song. Here’s the Wings’ version: