Antibody imprinting where prior antigen exposure shapes subsequent immune responses is well recognized, yet its long-term dynamics and epitope specificity remain poorly understood. Here, we studied individuals sequentially infected with SARS-CoV-1 and SARS-CoV-2 over two decades and observed a persistent imprinting effect of primary SARS-CoV-1 infection on subsequent SARS-CoV-2 BF.7 breakthrough infection. Approximately 60% of isolated monoclonal antibodies were SARS-CoV-1-imprinted, targeting conserved receptor-binding domain regions, whereas 37% overcame imprinting to recognize the SARS-CoV-2 receptor-binding motif overlapping the ACE2-binding site. Germline analysis revealed that SARS-CoV-1 imprinting was predominantly associated with IGHV1-8 and IGHV4-39, whereas SARS-CoV-2-focused responses preferentially utilized IGHV1-69 and IGHV3-53/66, with distinct heavy–light chain pairing predicted by AlphaFold3 and confirmed by crystallography. Notably, a subset of SARS-COV-1-only antibodies retained germline features and neutralizing activity two decades post-infection. One exceptionally broad neutralizing and imprinted antibody, THZ937, conferred protection against contact and airborne transmission of Omicron EG.5.1 in hamsters, demonstrating the functional relevance of durable imprinting. Together, these findings define the longevity and epitope specificity of antibody imprinting at the monoclonal level and inform strategies for pan-sarbecovirus vaccine design.