Monoclonal antibodies (mAbs) now dominate the global biologics landscape, with sustained clinical and commercial impact across oncology, immunology, and infectious disease. Ensuring reliable quality, safety, and efficacy throughout development and lifecycle management depends on a rigorous Chemistry, Manufacturing, and Controls (CMC) framework. This review provides a detailed, comparative synthesis of international CMC expectations for mAbs, anchored in International Council for Harmonisation (ICH) guidelines—Q5A(R2) (viral safety), Q5C (stability), Q6B (specifications), Q8(R2), Q9(R1), Q10, Q11, Q12, and the analytical pair Q14/Q2(R2)—and complemented by U.S. Food and Drug Administration (FDA) and European Medicines Agency (EMA) guidances. We elaborate practical strategies for CQA-driven product and process understanding; specification setting that integrates clinical relevance, process capability, and assay variability; analytical modernization (ATP-based method development, multi-attribute methods, advanced glycoanalytics); viral safety modernization (molecular detection and orthogonal clearance validation); and Process Analytical Technology (PAT) with elements of real-time release testing (RTRT). We further examine lifecycle agility through Q12 mechanisms (Established Conditions, post-approval change management protocols) and highlight emerging directions—digital CMC models, continuous/hybrid operations, immunogenicity risk integration, and sustainability metrics. Consolidated tables and figures provide at-a-glance operational guidance to support globally harmonized submissions for mAbs.