As early as 1925, Nella Larsen had decided that she wanted to be among the "New Negro" writers receiving considerable attention at the time. Initially writing short stories that were sold early in 1926 to a ladies magazine, she was rumored that year to be writing a novel. In a letter to her friend, Carl Van Vechten, she acknowledges, "it is the awful Truth. But, who knows if I'll get through with the damned thing. Certainly not I." In April 1927, Larsen and her husband, Elmer Imes, moved from Jersey City, New Jersey to Harlem to be closer to the cultural phenomenon. The following year, Larsen published her first novel Quicksand with New York-based publisher Knopf, and its favorable critical reception encouraged her ambitions to become known as a novelist. She published only these two novels (including Passing) and some short stories.
The 1920s in the United States was a period marked by considerable anxiety and discussion over the crossing of racial boundaries, the so-called "color line" between blacks and whites, exacerbated by the Great Migration, in which hundreds of thousands of blacks left the rural south for northern and midwestern cities, where, together with new waves of immigrants, they changed the social makeup. The practice of persons crossing the color line and attempting to claim recognition in another racial group different from the one they were believed to belong to was known as "passing" even when it was based on a person's ancestry. As many African Americans had European ancestry in varying proportions, some appeared visibly European. The US history of slavery as a racial caste and the imposition of the one-drop rule in the early 20th century were used by whites to try to harden racial lines that were more fluid in history; at any time, the concept of race was "historically contingent." Although the exact numbers of people who passed is, for obvious reasons, not known, many estimates were made at the time. The sociologist Charles S. Johnson (1893–1956) calculated that 355,000 blacks had passed between 1900 and 1920.
A significant precedent for Larsen's depiction of Clare and Jack's relationship was the 1925 legal trial known as the "Rhinelander Case" (or Rhinelander v. Rhinelander). Wealthy, white Leonard Kip Rhinelander sued his wife, Alice Beatrice Jones, for annulment and fraud; urged by his family, he alleged that she had failed to inform him of her "colored" blood.
The case was also about status and class, as he had met her when she was working as a domestic. She contended that her mixed race was obvious, and she had never denied it. Although the jury eventually returned a verdict for Alice, it came at a devastating social cost for both parties; intimate exchanges between the couple were read out in court, and she was forced to disrobe partially in front of the jury in the judge's chambers in order for them to assess the darkness of her skin.
Larsen refers to the case near the end of the novel, when Irene wonders about the consequences of Jack discovering Clare's racial status: "What if Bellew should divorce Clare? Could he? There was the Rhinelander case." The case received substantial coverage in the press of the time, and Larsen could assume that it was common knowledge to her readers.