The composite hard roof in the Southeast Shanxi mining area exhibits characteristics of high strength and continuous interbedding, forming a hard rock combination layer that undergoes coordinated movement. Coupled with significant burial depth and intense mining-induced disturbances to the surrounding rock in this region, this condition readily leads to dynamic disasters, such as rock bursts, during the initial mining stages. Targeting the improvement of the stope boundary configuration in early mining as the entry point, a roof modification technology induced by energy-gathering blasting is proposed. Research indicates that a boundary condition of "three fixed edges and one simply supported edge" facilitates roof subsidence in the goaf, promotes the dense development of fractures along both the strike and dip of the roof, enhances the blocking effect on stress wave propagation, and weakens the energy-accumulating property of the composite hard roof. Deep-hole energy-gathering blasting in the rock layer increases the initial guided crack length for rock fragmentation by the explosive jet and reduces the required gas pressure for directional crack propagation, thereby promoting controlled crack extension and creating the fundamental conditions for transforming a fixed boundary into a simply supported one. The proposed boundary control and modification method via roof energy-gathering blasting was implemented in the 2319 and 1316 working faces. Engineering practice demonstrated that deep-hole energy-gathering blasting creates distinct fractured and cracked zones near and far from the boreholes, facilitating the transformation of the roof boundary condition from four fixed edges to three fixed and one simply supported during the initial mining phase. Compared with the unmodified working face, the first weighting interval at the 2319 face was reduced by 28%, and the accumulated elastic energy within the roof significantly decreased. At the 1316 working face, 94% of microseismic events had energy values within the 10,000–25,000 J range. The energy-gathering blasting successfully achieved stope boundary modification, subsequently promoting roof subsidence and caving after mining, thus preventing and controlling dynamic coal-rock disasters in the initial mining stages.