This study developed antimicrobial composite coatings from gelatin (GL) and carboxymethyl chitosan (CMCS) functionalized with carvacrol (CA) as a natural alternative for the preservation of strawberries. Films incorporated with 0%, 1.5%, and 3% CA were characterized by their physical, mechanical, and structural properties. The addition of CA significantly improved opacity, tensile strength, elongation-at-break, and thickness, while reducing water vapor permeability, moisture content, and solubility (p < 0.05). Spectroscopy and microscopy also confirmed CA’s uniform dispersion within the matrix. During 14 days of storage at 4 °C, strawberries coated with GL/CMCS/CA-3% significantly reduced weight loss (50.91%) and fungal contamination, improved firmness (79.31%), and maintained color and pH. Conversely, uncoated strawberries showed rapid declines in soluble solids, acidity, phenolics, anthocyanins, vitamin C, and antioxidant activity (p < 0.05). Microbial growth was effectively suppressed in coated fruits, while sensory profiles were drastically impaired in uncoated samples at the end of storage (p < 0.05). These results demonstrate that GL/CMCS/CA coatings can effectively preserve strawberry quality and extend shelf life without synthetic preservatives.