Extant literature shows two types of disruption: disruption-by-entry, where new entrants into an industry drive disruption, and disruption-from-within, where incumbents drive disruption. In this paper we break new ground by revealing and unpacking a third, untheorized process: disruption-by-proxy. We conceptualize disruption-by-proxy as a deliberate strategy whereby a technology provider creates a sustaining innovation in their core industry, secures technology adoption by powerful incumbents in their target industry, and thereby disrupts that industry and, potentially, other adjacent industries. The powerful incumbents act as disruptive proxies for the technology firm, which effectively drives business model change in one or more industries yet never seeks to extend beyond its core industry. To theorize this conceptualization, we explore the research question: “How does disruption-by-proxy unfold?” Our ethnographic study of a small technology firm shows how a disruptor engages in iterative phases of proxy testing of selected product-market bundles, (re)envisioning the disruptive process and potential industry end states, and advancing the technology whilst seeking to optimize its fit with emergent understandings of incumbent tolerance for adoption and disruption. Our process model theorizes disruption-by-proxy as an inherently collaborative and industry-spanning strategy that locates the instigator and driver of disruption permanently outside the disrupted industry or industries.