The creep properties and nonlinear energy evolution characteristics of granitic gneiss under high ground stress are investigated in this study. Basic mechanical property tests were conducted on the rock, followed by triaxial creep tests under high confining pressure. The research findings reveal the nonlinear energy evolution mechanism of granitic gneiss under high ground stress, providing a foundation for further investigation into the creep behavior of deeply buried rock masses. The experimental results show that under the same stress level, compared with the conventional test, rocks in the creep test exhibit a higher energy dissipation and a lower capacity for storing elastic energy. As the confining pressure increases, the promoting effect on energy accumulation is more significant than the inhibiting effect. The energy storage coefficient for creep compression ranges from 0.7–0.75, while for conventional compression it ranges from 0.79–0.94. In conventional tests, cracks in the rock begin to propagate periodically when the loading stress reaches 81.1% of the peak stress. Similarly, cracks start to propagate irregularly in the rock when the loading stress reaches 84.2% of the peak stress. In creep tests, both high confining pressure and step loading delay the onset of periodic and irregular fractures in deeply buried creep rocks.