Photoredox catalysis relies on light-induced electron transfer, leading to a radical pair in a solvent cage. For productive reactions to occur, the oxidized donor and reduced acceptor must escape from the solvent cage before spontaneous reverse electron transfer can occur. This study demonstrates the crucial role of cage escape in three benchmark photocatalytic reactions: aerobic hydroxylation, reductive debromination, and an aza-Henry reaction. Using ruthenium(II) and chromium(III) photocatalysts, which exhibit different cage escape quantum yields, the authors determined quantitative correlations between product formation rates and cage escape quantum yields. These findings are rationalized within the framework of Marcus theory for electron transfer. The study highlights that photoredox reaction rates and quantum yields are governed by cage escape, and that luminescence quenching experiments alone are insufficient for understanding photoredox reactivity.Photoredox catalysis relies on light-induced electron transfer, leading to a radical pair in a solvent cage. For productive reactions to occur, the oxidized donor and reduced acceptor must escape from the solvent cage before spontaneous reverse electron transfer can occur. This study demonstrates the crucial role of cage escape in three benchmark photocatalytic reactions: aerobic hydroxylation, reductive debromination, and an aza-Henry reaction. Using ruthenium(II) and chromium(III) photocatalysts, which exhibit different cage escape quantum yields, the authors determined quantitative correlations between product formation rates and cage escape quantum yields. These findings are rationalized within the framework of Marcus theory for electron transfer. The study highlights that photoredox reaction rates and quantum yields are governed by cage escape, and that luminescence quenching experiments alone are insufficient for understanding photoredox reactivity.