Authors accomplish direct characterization when they closely describe characters's looks and traits. Sometimes it is the narrator who provides it, or it can be the words of another character in the work.
Dexter Green has a decisive and self-confident personality, seen first on the day that he abruptly quits his job as a caddy. He tells Mr. Jones, who pleads with Dexter to caddy for him, that "I decided I was too old." Dexter's winter dreams lead him to sidestep the then-conventional worlds of the stock market and sales to become a self-made businessman. He "borrowed a thousand dollars on his college degree and his confident mouth, and bought a partnership in a laundry."
Once Dexter has prospered, he returns briefly to the golf club where he had caddied as a boy and finds that he "was impressed by the tremendous superiority he felt toward Mr. T. A. Hedrick, who was a bore and not even a good golfer any more." Dexter has surpassed the men whom he had formerly held in awe.
Fitzgerald builds the characterization of Dexter Green through descriptions of his confident decision-making and unshakeable belief in himself. Dexter is widely regarded as a good catch because "he was an eligible young man, now, and popular with down-town fathers."