Stories almost invariably contain conflict across multiple levels (even if some are more prominent than others). "The Secret Life of Walter Mitty" is no exception, tying together external and internal conflict. Usually, conflict tends to be divided into four kinds: person versus self; person versus person; person versus society; and person versus nature. "The Secret Life of Walter Mitty" utilizes the first three of these four categorizations.

To begin, the most apparent source of external conflict lies between Walter Mitty and his wife. Hers is a very dominant personality, which appears to exert a stifling effect on Walter himself. But external conflict is hardly limited to his wife alone. Walter emerges as someone ill at ease within conventional society, constantly receiving its disapproval.

Finally, there is internal conflict as well. When looking at the tenor of his daydreams, we see consistently a strong, domineering force of personality by which Walter Mitty can play the role of the hero, even as he is continually stifled by the society around him. There is a tension between the reality that he experiences and the daydreams to which he retreats. This reflects the conflict internal to Mitty himself and his dissatisfaction with his life.