Staphylococcus pseudintermedius is a zoonotic pathogen that can cause life-threatening infections in animals and humans. The study of methicillin-resistant S. pseudintermedius (MRSP) and its ability to produce biofilms is important to select the most suitable treatment. The prevalence and characteristics of S. pseudintermedius isolated from dogs admitted at the Veterinary Teaching Hospital, Prince of Songkla University, Thailand were assessed. Results showed that 28.30% (15/53) of the isolates were MRSP. Amplification of the mecA gene was observed in 93.33% (14/15) MRSP. Methicillin-resistant strains revealed co-resistant patterns against other antibiotics, including chloramphenicol, clindamycin, tetracycline, clarithromycin, ciprofloxacin, and trimethoprim. In this study, all bacterial isolates produced biofilms, while 90.55% of S. pseudintermedius isolates were strong or moderate biofilm producers. Most (45–60%) of the resistant strains were strong biofilm producers, while the correlation between biofilm production and antibiotic resistance was not statistically significant. This is the first study in southern Thailand to investigate the drug-resistant profile of S. pseudintermedius and its ability to form biofilm. The results will contribute to a better understanding of the emergence and prevalence of antimicrobial resistance in S. pseudintermedius.