<p>Probiotic fermentation with a defined consortium (<i>Saccharomyces cerevisiae</i>, <i>Lactobacillus helveticus</i>, and <i>Lactobacillus delbrueckii</i> subsp. <i>bulgaricus</i>) successfully transformed pumpkin juice into a functional beverage with enhanced bioactivity and appealing aroma. The fermented product achieved a high viable count of 7.37 log CFU mL⁻¹, along with significant increases in vitamin C, total phenolics, flavonoids, and carotenoids compared to unfermented juice. Fermentation also imparted a distinct volatile profile enriched with esters and alcohols—such as phenylethyl alcohol, phenethyl acetate, and ethyl caprylate—which contributed intense fruity and floral notes, as confirmed by OPLS-DA and sensory evaluation. The resulting juice retained its original color (ΔE &lt; 2) and developed desirable rheological behavior. Thus, accordingly the pumpkin juice fermented with the composite probiotics received the highest sensory evaluation. This study demonstrates that composite-culture fermentation effectively enhances the nutritional value, aroma, and sensory quality of pumpkin juice, highlighting its potential as a novel probiotic beverage.</p>