The objective of this paper was to assess the environmental performance of the system of RuBisCo protein extraction and isolation from sugar beet leaves. Life cycle assessment (LCA) calculations have been completed to identify and quantify the environmental impacts from a cradle-to-cradle perspective covering seven subsystems: milling and extraction, heat treatment, centrifugation, microfiltration, ultrafiltration, chromatography and spray drying. In this paper, six environmental impact categories were analyzed: global warming potential, ozone layer depletion, energy demand, eutrophication potential, acidification potential, and land use. When RuBisCo protein extraction and isolation from different raw materials are compared, the only crop that has a lower environmental impact than sugar beet leaves is alfalfa, while the higher environmental impact has yellow mustard, ryegrass (mixture), Italian ryegrass, Brussels sprouts, English ryegrass, carrot leaves, leaf radish, and chicory. The comparison of environmental impact categories of different protein concentrates indicated that protein powder containing RuBisCo affected the environment less than egg protein concentrate. Direct comparison to other highly functional plant proteins was not possible as these are not in the market or have no LCA data available. RuBisCo was more environmentally impacting than regular soy protein. Our results for RuBisCo were in accordance with the low end of the range of results for microalgae, which is representing Chlorella HTF (heterotrophic fermenter), for most of the analyzed impact categories. This study found that the largest contributor to the environmental profile of the entire system of RuBisCo protein extraction and isolation from sugar beet leaves is the usage of electricity, while mitigation options for optimization of environmental impacts rely on the energy pinch approach for spray drying.