In this study, four essential oils, namely, thyme (Thymus vulgaris L.), clove (Eugenia caryophyllus from dried floral buds of Syzygium aromaticum), rosemary (Rosmarinus officinalis L.), and tea tree (Melaleuca alternifolia aetheroleum) obtained from Romanian production (Fares Co., Orăştie, Romania) are intent to be used as components in bioactive food packaging. Therefore, as a first step, it should be worthwhile to comparatively evaluate the composition and antimicrobial/antioxidant activity of these four EOs. Antifungal and antibacterial activity against three target food spoilage fungi (Aspergillus brasiliensis, Fusarium graminearum, and Penicillium corylophilum) and three potential pathogenic food bacteria (S. aureus, E. coli, and L. monocytogenes) have been evaluated. The minimum inhibitory concentration (MIC) concentration was established in each case. The antioxidant activity was determined, and the most efficient oil for each type of activity was established. Preliminary tests on the EO encapsulation into chitosan films and their antimicrobial activity against the spoilage of beef meat showed promising results, a detailed presentation for which will be provided in a future paper.