Thermo-mechanical creep-fatigue (TMCF) behaviors of a TiAl alloy were investigated by conducting various creep, creep-fatigue, and thermo-mechanical tests and performing detailed microstructural analysis. A new creep model was proposed to unify primary strain hardening and tertiary accelerating damage effects. The TMCF failure of TiAl alloys is accompanied by the crack initiation from surface oxides/carbides and mixed transgranular and intergranular cracking. It revealed that introducing thermo-mechanical cycles significantly reduces the creep damage rate during the creep dwell stage and the fatigue process, i.e., the creep-delaying effect, which is attributed to the non-proportional strengthening effect induced by thermal cycles. A life model based on the average minimum creep strain rate was proposed to predict the creep-dominated TMCF life. This model incorporates the complex creep-fatigue interactions on creep damage and demonstrated good agreement with experimental results under varying loading conditions. The present work provides new insights into understanding the creep-dominant thermo-mechanical damage evolution of TiAl alloys.