The emergence of Large-Format Printing (LFP) technology has revolutionised global visual communication, significantly impacting Nigeria's Graphic Design Practice (GDP). This study explores the prevailing influence of LFP in 21st-century Nigeria to propose sustainability measures and mitigate developmental challenges. A mixed-methods approach was employed, primarily utilizing qualitative data from interviews and participant observation, processed via content analysis. This was supported by quantitative measures using Likert Scale questionnaires to evaluate the attitudes and perceptions of graphic designers regarding LFP’s influence on the industry. Findings reveal a dual impact. High levels of developmental growth were identified in areas of scale, output quality, creative freedom, and operational efficiency. These results suggest that LFP has successfully addressed the limitations of the pre-21st-century era, which was dominated by manual letterpress, offset printing, and hand-painted signboards. Conversely, the study uncovered significant challenges, including market oversaturation, intellectual property piracy, and colour inconsistency, the latter of which directly contests the perceived improvements in quality. The study concludes that while LFP technology has empowered innovation and growth within the Nigerian industry, its full potential is hindered by the proliferation of unaccredited freelance practitioners. To ensure sustainable development and fully harness this transformative technology, the study recommends targeted technical training and mandatory professional accreditation by the Chartered Institute of Professional Printers of Nigeria (CIPPON) and the Advertising Regulatory Council of Nigeria (ARCON) as a standard for practice.