Damask rose (Rosa damascena Mill.), a fragrance flower from the Rosaceae family, is renowned for its aromatic fraction, which has applications in the cosmetic and medicinal industries. Nonetheless, during the extraction process, several by-products are generally disposed to the environment. Mon Dang Prasert (MD), Mon Klai Kangwon (MK), and Bishop's Castle (BC) are the most commonly grown varieties in Thailand with commercial potential. In this work, their aromatic profiles were described via SPME-GC-MS. The rose essential oil primarily consisted of phenylethyl alcohol, with concentrations of 1.03% for MD, 1.03% for BC, and 1.31% for MK. This compound is responsible for the characteristic flowery, sweet, rosy, and bready fragrance. Following this is furfural, a compound known for its unique sensory profile, featuring a fresh, fragrant, and almond fragrance. Followed by the conventional extraction process, three different fractions of by-products were produced, namely distilled water (D), hydrosol (H), and rose dreg (R). Subsequently, the antioxidant properties of these by-products were evaluated. The H fraction exhibited the highest total phenolic content with values of 10.08, 10.28, and 8.14 mg GAE/g dried sample for MD, MK, and BC samples, respectively. The results were consistent, with the total flavonoid content also being highest in the H fraction. The H and R fractions demonstrated positive antioxidant activity, as indicated by the results obtained in the DPPH, ABTS, and FRAB assays. An anti-microbial assay of these fractions against Staphylococcus aureus, Propionibacterium acnes, S. epidermidis, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans illustrated no positive activity in any of the fractions. Consequently, MK flower provided the strongest intensity of floral fragrance. The antioxidant capacity of the by-product indicated that the H fraction contained significant advantages for antioxidants, rendering it suitable for the utilization of intermediate material in the production of cosmetic and medicinal products.