Climate change is increasing the frequency of droughts, raising the need for sustainable irrigation management in viticulture. This study evaluated the effects of three deficit irrigation regimes—well-watered (WW), mild deficit (MiD), and moderate deficit (MoD)—implemented through the decision support system Vintel^® in a Pinot gris vineyard in Friuli Venezia Giulia (Italy). Vine physiology, grape ripening, and wine aroma profile were assessed across two seasons. The water deficit treatments modulated yield parameters (specifically, cluster weight was reduced by 12% and 10% for Mid and Mod as compared to WW) and delayed sugar accumulation, particularly under MoD (9% Brix reduction as compared to WW). While basic wine composition largely reflected grape maturity, volatile aroma compounds showed variable responses to irrigation and were strongly modulated by seasonal conditions. MiD had a minimal impact on the aroma profile, whereas MoD led to reduced sugar and altered volatile composition, especially under hot and dry conditions. DSS-based mild-deficit irrigation can be adopted to reduce vineyard water consumption without compromising Pinot gris wine quality.