Aromatic textiles are a significant application of aromatherapy, and the durability and washability of such textiles are critical performance metrics. In this study, in situ embedded aromatic yarns were developed to enhance the longevity and wash resistance of the embedded fragrance. Electrospun nanofibers were employed as efficient carriers for aromatic agents, with ylang ylang oil (YYO) selected as the core material and chitosan (CS) as the wall material. The nanocapsules were prepared using ionic gelation to encapsulate the aromatic compound. The morphology, cross-linking, and thermal stability of the nanocapsules were characterized using scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. The results indicate that cross-linking occurred between CS and sodium tripolyphosphate, YYO was effectively encapsulated within the nanocapsules, and the thermal stability was enhanced. These nanocapsules were then incorporated into nanofibers through electrospinning, which were subsequently deposited onto cotton webs, forming a novel aromatic yarn through further processing. The morphology, mechanical properties, and aromatic properties of the aromatic yarns were characterized. As a result, the nanofibers were coated inside the yarn, and the retention rate of YYO remained at 67.25% after 28 days. After 20 washing cycles, the YYO content in the aromatic yarn was 0.5 mg/g, indicating strong controlled-release performance and wash resistance. This study provides insights into the preparation of textiles with long-lasting aromatic properties and durability.