Tendons and ligaments connect to bone through a highly specialized interface called the enthesis. Each component of the enthesis enables the smooth transition of forces from a relatively compliant tendon or ligament to the dense bone. However, tendon and ligament injuries frequently occur at the enthesis due to stress concentrations and current repair strategies do not result in the re-formation of the graded tissue structure, leading to high re-tear rates. There is a critical need to develop strategies to re-create the native zonal enthesis architecture. To address this need, we used insights from enthesis development to guide our studies in adults. Since traditional tendon-to-bone reattachment surgeries do not lead to enthesis re-formation, we used anterior cruciate ligament (ACL) reconstructions, which give rise to zonal attachments when tendons are passed through bone tunnels that resemble the four-zone enthesis architecture, as our test platform. We began by optimizing attachment formation in a murine ACL reconstruction (ACLR) model by investigating the effect of graft fit in the tunnel. We found that creating a press-fit of the graft against the tunnel walls promoted mineralized fibrocartilage (MFC) formation during the repair process. Next, to establish the key regulators that lead to zonal attachment formation after ACLR, we performed surgeries in αSMACreERT2 mice, which labeled a mesenchymal progenitor population in the bone marrow that expanded in response to the tunnel drilling and ultimately created the attachments in the tunnels. We demonstrated that this mouse model could efficiently target cells that go on to form the attachments, allowing us to study signaling pathways that regulate attachment formation in these cells. We modulated the Hh signaling pathway, which is critical for enthesis development and maturation, in our ACLR model both genetically and pharmacologically. We found that Hh signaling played a biphasic role in promoting attachment formation after ACLR, both by increasing the early expansion of the progenitor pool that goes on to make the attachments and by increasing fibrocartilage differentiation in the later stages of healing. Together, this work establishes key mechanical and molecular factors that regulate attachment formation in the adult.