The regulatory focus on quantifiable sustainable investing shifts investors’ demand toward impact products, which creates challenges in achieving their primary target of outperformance. This study demonstrates the implications of sustainable investment in actively managed credit portfolios using carbon emissions, Sustainable Development Goals (SDGs), and green bonds. All three measures exhibit a low correlation with systematic factors, such as value and momentum, providing an opportunity for a sustainable alpha. Furthermore, we demonstrate a concave relationship between outperformance and sustainability. Therefore, systematic investors achieve a sustainable portfolio at a low cost, whereas sustainability-oriented investors harness factor returns to meet their initial targets.