Biofilm-associated infections remain a major clinical challenge due to the heightened resistance of biofilm-forming pathogens to conventional antibiotics. This study evaluated the antimicrobial and anti-biofilm activities of Vernonia amygdalina, Ocimum gratissimum, and Kalanchoe pinnata plants widely used in African traditional medicine against clinically isolated multidrug-resistant organisms. Methanolic, ethanolic, and aqueous leaf extracts were prepared and tested against Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans using agar well diffusion, minimum inhibitory concentration (MIC), minimum bactericidal/fungicidal concentration (MBC/MFC), and synergy assays (FICI). Results showed that methanolic extracts produced the highest zones of inhibition (up to 30.0 mm), followed by ethanolic and aqueous extracts. Synergistic interaction was observed in the combined extracts (ΣFICI = 0.19), particularly effective against E. coli and C. albicans. The observed antimicrobial effects are attributed to phytochemicals including sesquiterpene lactones (vernodalin, vernomygdin), flavonoids (luteolin), saponins, and alkaloids, which are known for disrupting microbial membranes and inhibiting biofilm formation. This study highlights the therapeutic potential of these ethnobotanical species as sources of multi-targeted anti-biofilm agents. Further studies are recommended to isolate specific bioactives, quantify biofilm disruption, and evaluate cytotoxicity to support clinical application.