This study investigated the effects of heat-induced aging on the nutritional composition, physicochemical properties, sensory profiles, and biological activities of Allium schoenoprasum L. (AS) bulbs over a 7-day period. Key parameters evaluated included instrumental color, texture, bioactive compound content (total phenolics and total flavonoids), antioxidant capacity (ABTS^•+ scavenging activity and ferric reducing antioxidant power, FRAP), and anti-inflammatory potential (bovine serum albumin denaturation inhibition). The results demonstrated that thermal aging for 7 days resulted in a significant reduction in moisture content (from 65.18 to 23.33 g/100 g fresh weight, FW) and a transition to a distinct black color (L* value decreased from 76.91 to 26.94). Thermal treatment induced increases in contents of reducing sugars and total soluble solids. These shifts effectively enhanced the flavor profile and overall sensory acceptability (score increased from 5.57 to 8.29). Importantly, although total phenolic and total flavonoid contents initially declined (days 1–2), they substantially increased during the later stages of aging (days 3–7). This accumulation of phenolic compounds resulted in a significant enhancement in antioxidant capacity, evidenced by increases in ABTS^•+ scavenging activity and FRAP. Conversely, the specific anti-inflammatory capacity of the aged AS bulbs was significantly lower compared to the fresh samples. These findings provide critical insights into the dynamic physicochemical transformations of AS during aging, assisting manufacturers in optimizing processing parameters to develop high-quality black AS products with targeted functional properties.