Aryl hydrocarbon receptor (AhR) antagonism is known to expand human hematopoietic stem cells (HSCs). However, its regulatory effect on the lineage-skewed differentiation of HSCs has not been sufficiently studied. Here, we investigate the effect of the AhR-selective antagonist CH223191 on the regulation of HSC differentiation. Consistent with the well-known effects of AhR antagonists, CH223191 treatment increase phenotypic HSCs (Lin-CD34 + CD38-CD90 + CD45RA-) and preserves their functionality. On the other hand, CH223191 leads to an overall expansion of megakaryocyte (MK)-lineage populations, such as MK progenitors (MKps, CD34 + CD41 +), immature MKs (CD41 + CD42b-), and mature MKs (CD41 + CD42b +), and it also activates MK/platelet-associated signaling pathways. Furthermore, CH223191 expands MKps, mature MKs, and p-selectin (CD62p)-positive platelet-like particles in immune thrombocytopenia (ITP) patient bone marrow (BM). These results highlight the numerical expansion of human MK-lineage progeny through AhR antagonism with CH223191. This approach using CH2231291 may be applicable in the development of auxiliary treatment regimens for patients with abnormal thrombopoiesis.