Upon activation, naïve T cells undergo rapid proliferation and differentiation, giving rise to clonally expanded populations specifically tailored for an effective immune response. To meet the heightened bioenergetic and biosynthetic demands associated with activation, T cells adapt and reprogram both their metabolism and transcriptome. Beyond this, T cells are also able to dynamically adapt to fluctuations in the microenvironmental nutrient levels. While the adaptability of T cells is a well-established hallmark of their functionality, the molecular mechanisms by which metabolic responses underpin this flexibility remain incompletely defined. Acetyl-CoA, with its role as a central metabolite in mitochondrial ATP production, and a substrate for nuclear histone acetylation reactions, emerges as a key player in a metabolic-epigenetic axis. Recent evidence indicates that enzymes responsible for generating acetyl-CoA can translocate to the nucleus, supporting sub-cellular local acetyl-CoA production. Here, we explore the impact of acetyl-CoA metabolism on T cell functionality within different subcellular compartments and highlight the potential for intervention in acetyl-CoA metabolic pathways in T cell-driven autoimmune diseases and cancers.