Tsuga canadensis (Eastern Hemlock) is a keystone tree species currently experiencing high mortality in southeastern US forests due to Hemlock Woolly Adelgid (Adelges tsugae; HWA) invasion. Investigating the impacts of concurrent climate change on Eastern Hemlock is important given its potential direct effects on this species and possible interactions of climatic factors with the continued spread of HWA. We conducted a 2-factorial experiment in controlled-environment growth chambers to test for the main effects and interactions of projected atmospheric CO₂ concentrations and transitional-season warming on gas-exchange traits of Eastern Hemlock saplings collected from a northern Georgia field site. We hypothesized that elevated CO₂ would increase photosynthesis and that warming would not influence photosynthesis, given the demonstrated capacity for photosynthetic temperature-acclimation in this species. Saplings in elevated CO₂ exhibited ∼30% greater leaf-level photosynthesis (A) and ∼35% greater maximum light-saturated photosynthesis (A_max) than saplings in ambient CO₂. In contrast, warming did not influence A or Amax as a main effect. However, significant treatment interactions suggest that the response of Eastern Hemlock to rising CO₂ could be impacted by associated warming. Specifically, when saplings were grown in elevated CO₂, warming was associated with reductions in A_max, rate of respiration in the dark, and stomatal conductance, but these variables were not influenced by warming when combined with ambient CO₂. An increase in the light-saturation estimate with elevated CO₂ across temperature-treatment levels indicates that CO₂ can be a limiting factor for Eastern Hemlock, but significant treatment interactions suggest that the capacity for this species to utilize increased CO₂ may be impacted negatively by warming.