Realist novels strive to present an objective image of reality by mainly using impersonal impartial narrators. Moreover, an intrusive narrator leads to a fabricated narrative and overshadows its verisimilitude. The present study aimed to investigate all kinds of intrusion by narrators in the Persian novels from 1921 till 1941 in terms of realism. To do so, first the signs of narrator intrusion were identified and categorized in the novels under study. Then, narrator intrusion was investigated in terms of components of realism. The main narrator intrusion techniques included narrator’s self-expression, explanations about narrative act, judgments about story characters and actions, generalizations of emotions and actions of characters, and delivery of sociopolitical speeches by the narrator/author. The results revealed that some narrator intrusion techniques, especially narrator’s self-expression and explanations about narrative act, had roots in the novelty of the novel genre and had been influenced by the then common narrative models in the traditional genres such as storytelling and the like. Explanations about narrative act may weaken the illusion of reality and verisimilitude by highlighting the constructivism of a literary work. Furthermore, a belief in the educational function of the literature and the delivery of long ideological speeches would lead to the inconsistency of journalistic missions with the realist criteria for novel narration and thus would undermine an absent or impartial narrator.