Ancient giant sequoia groves that were sustained by frequent fire for millennia recently experienced large-scale mortality from extreme wildfires after more than a century of fire exclusion. We analyzed tree-level satellite imagery and surrounding forest structure from airborne lidar of 26,000 sequoias to quantify mortality rates and drivers following two large wildfires from 2020-2021 in Sequoia and Kings Canyon national parks. Our study highlights the mitigative effects of recent prescribed burns (within 10 years) on reducing mortality of thousands of trees across diverse burn conditions. This work informs restoration and management strategies specifically targeting giant sequoias to bolster their resilience amid more extreme wildfire regimes.