In the late nineteenth-century United States, kerosene became a universal illuminant for artificial lighting, providing its users with a shared material environment. While kerosene users employed the fluid not only for lighting but also for washing, cooking, and cleaning, they had to deal with the material’s risks, such as fires and explosions. With the help of chemists and domestic advisors, American consumers adapted to this ambivalent material condition, weaving kerosene into their economic life and social thought. In so doing, some consumers identified as a “professional class” that navigated within this material environment through their own expertise—which paralleled their economic struggle within a rapidly growing but volatile political economy during the Gilded Age. As Standard Oil’s monopolization of the kerosene business became a substantial issue in national politics, this social consciousness among kerosene users attracted anti-monopolists like Ida Tarbell. Because Standard Oil had lowered the consumer price, these reformers sought an alternative rationale to persuade kerosene-consuming households to participate in the antitrust movement against the company. Examining how these progressive reformers turned kerosene consumers’ social identity to their political ends, this article sheds new light on the relationship between the energy transition, consumer culture, and American capitalism.