Mesenchymal stromal cells (MSCs) are multipotent progenitors supporting bone marrow hematopoiesis. MSC have an efficient DNA damage response (DDR) and are consequently reatively radio-resistant cells. Therefore, MSCs are key to hematopoietic reconstitution following total body irradiation (TBI) and bone marrow transplantation (BMT). The bone marrow niche is hypoxic and via the heterodimeric transcription factor Hypoxia-inducible factor-1 (Hif-1), hypoxia enhances the DDR. Using gene knock-down, we have previously shown that the Hif-1α subunit of Hif is involved in MSC radio-resistance, however its exact mechanism of action remains unknown. In order to dissect the involvement of Hif-1α in the DDR, we have generated using CRISPR/Cas9 technology, a stable MS5 mouse MSC cell line lacking Hif-1 expression. Herein, we show that it is the whole Hif-1 transcription factor, and not only the Hif-1α subunit, that modulates the DDR of mouse MSCs, and that this effect is dependent upon the integrity of the DNA binding domain. We have also characterized the Hif-1α-dependent proteomic changes undergone by hypoxic MS5 cells. These findings have important implications for the modulation of MSC radio-resistance in the context of BMT and cancer.