Multidrug-resistant bacteria represent a serious public health concern due to their reduced susceptibility to multiple antibiotics and their capacity to form biofilms, which complicates treatment and contributes to persistent infections. Total phenolic compounds and flavonoids were quantified using spectrophotometric methods. The antimicrobial and antioxidant properties of the extracts were evaluated using agar diffusion, microdilution, and various antioxidant assays, respectively. Antibiofilm activity was determined by measuring the inhibition of biofilm formation in the tested bacterial strains. Phytochemical analysis revealed high levels of polyphenols (1.973 ± 0.064 to 4.501 ± 0.082 g GAE/100 g DW) and flavonoids (0.150 ± 0.018 to 0.304 ± 0.031 g RE/100 g DW). These findings are consistent with the notable antioxidant activity observed, with IC₅₀ values ranging from 30.8 to 491.3 µg/mL. Furthermore, the extracts exhibited significant antimicrobial activity against Staphylococcus aureus and Staphylococcus epidermidis, with inhibition zone diameters ranging from 10.31 to 14.13 mm. The MIC ranged from 0.23 to 0.94 mg/mL, while the MBC varied between 0.47 and 1.88 mg/mL. Moreover, all extracts significantly reduced biofilm formation compared to the untreated control, with inhibition rates ranging from 6.47 ± 0.5% to 72.17 ± 2.50%, highlighting their strong antibiofilm potential. This study highlights the potential of date seed extracts as a natural source of bioactive compounds capable of inhibiting biofilm formation and combating associated bacterial resistance.