Beyond his place among the Vanir in the mythological texts, Njord appears in a very different guise in Snorri Sturluson's Ynglinga saga, the opening section of his Heimskringla, a history of the kings of Norway that traces the Norwegian royal line back through a legendary Swedish dynasty called the Ynglings. There, in a euhemerizing move typical of medieval Christian writers handling pagan material, Snorri presents Njord not as a god worshipped in cult but as an early, historicized king of the Swedes, said to have ruled after Odin himself, a popular ruler under whose reign the land enjoyed such peace and abundant harvests that the Swedes came to believe he governed the prosperity of the year, before dying and being succeeded by his son Freyr, who continues the same royal line in the saga's account. This treatment folds Njord and Freyr's association with wealth, peace and agricultural abundance directly into a narrative of legendary Swedish kingship, presenting the gods' supposed benefits to humanity as the achievements of unusually effective, later-deified rulers rather than as the acts of literal deities, a rationalizing approach Snorri and other medieval Christian authors applied to Norse mythological material to preserve and transmit it without asserting its literal religious truth.
Whether any genuine folk memory of an early Swedish ruler lies behind this account, or whether Snorri simply mapped an existing god onto the format of a royal genealogy for narrative convenience, remains a matter of scholarly discussion, but the Ynglinga saga's version of Njord shows how thoroughly Old Norse mythological material could be reworked into pseudo-historical royal chronicle once its original religious context had passed.