Harvest weed seed control (HWSC), an evolving strategy in weed management, is highly effective for the control of a variety of weed species in North American cropping systems. Previous devices for weed seed devitalization at harvest have been limited to tow behind and integrated combine systems. The potato vine crusher (PVC) is a harvester-mounted set of rollers originally designed for crushing and control of Ostrinia nubilalis (Hübner) larvae during potato (Solanum tuberosum L.) harvest. To evaluate the potential of the PVC for HWSC, we conducted stationary testing of spring tension and roller speed settings to maximize devitalization of lambsquarters (Chenopodium album L.), the most problematic weed species in Canadian potato production. In addition, we evaluated the efficacy of the PVC for the devitalization of several pernicious weed species under controlled conditions and during a simulated harvest. Increasing PVC spring tension reduced the devitalization of lambsquarters seed, whereas roller speed had minimal effect. In contrast, maximized spring tension and minimized roller speed reduced lambsquarters emergence (53%) in soil. Hypocotyl and radicle elongation was observed from lambsquarters seed fragments under controlled conditions, potentially contributing to increased control in soil through fatal germination. High levels of seed devitalization (65%–94%) were observed for all species under controlled conditions. During simulated harvest, control of large weed seeds (50%–63%) was observed, whereas smaller seeds were not impacted, signifying the importance of seed size for PVC efficacy. These studies demonstrate the PVC as a promising new tool for HWSC in Canadian potato production systems.