<p>The increasing demand for sustainable food preservation and eco-friendly packaging has highlighted the potential of protein hydrolysates derived from animal by-products as natural bioactive ingredients. These hydrolysates exhibit antioxidant and antimicrobial properties, making them promising alternatives to synthetic additives in meat and seafood products. In this review, a structured literature search was conducted to gather studies on animal-based by-product protein hydrolysates, their production methods, bioactivities, and applications in active edible film/coatings for meat and seafood preservation. Searches were carried out across major scientific databases. Data were collected from scientific original articles published in 2021–2025 to ensure coverage of the most recent developments, technological innovations, and emerging trends in protein hydrolysates and their applications in sustainable food packaging. The review discusses hydrolysis methods, factors affecting peptide composition and bioactivity, and emerging processing technologies such as ultrasound, ohmic heating, and green extraction methods. It also highlights strategies for combining hydrolysates with essential oils, nanoparticles, or other bioactive compounds to achieve synergistic antioxidant and antimicrobial effects. Research has shown that the impact of edible active films containing protein hydrolysates on extending shelf-life is attributed not only to the increased bioactivity of the films but also to improvements in their mechanical strength and barrier properties against light, oxygen, and moisture. Despite their advantages, challenges remain, including variability in raw materials, potential interactions with food matrices, standardization issues in industrial-scale production, and regulatory gaps. The stability, migration, and sensory impacts of hydrolysate-enriched films also require further research. Finally, this review briefly discusses emerging digital and artificial intelligence–based approaches, including large language models, as supportive tools for literature analysis, peptide screening, and preliminary bioactivity prediction. These tools are presented as prospective aids rather than established solutions, and their application in protein hydrolysate–based active packaging remains at an early stage, requiring further experimental validation.</p>