Solid‐state (SS) NMR spectroscopy is a powerful technique for studying challenging biological systems, but it often suffers from low sensitivity. A longitudinal relaxation optimization scheme to enhance the signal sensitivity of HSQC experiments in SSNMR spectroscopy is reported. Under the proposed scheme, the 1H spins of 1H–X (15N or 13C) are selected for signal acquisition, whereas other vast 1H spins are flipped back to the axis of the static magnetic field to accelerate the spin recovery of the observed 1H spins, resulting in enhanced sensitivity. Three biological systems are used to evaluate this strategy, including a seven‐transmembrane protein, an RNA, and a whole‐cell sample. For all three samples, the proposed scheme largely shortens the effective 1H longitudinal relaxation time and results in a 1.3–2.5‐fold gain in sensitivity. The selected systems are representative of challenging biological systems for observation by means of SSNMR spectroscopy; thus indicating the general applicability of this method, which is particularly important for biological samples with a short lifetime or with limited sample quantities.