Cancer progression involves systemic immune suppression and tumor recurrence facilitated by increased splenic protumoral myelopoiesis. To address this clinical challenge, we developed an engineered Trojan Mycobacterium as a trained immunity (TI)-mediated splenic myelopoiesis converter (t-SMC). This design provides an intravenously injectable anisotropic TI inducer with an aspect ratio of 3.6 for preferential spleen targeting and cellular uptake via a Mycobacterium "peeling-off and masking-up" strategy with human serum albumin incorporating an enzyme‑activatable Toll‑like receptor 7/8 agonist that boosts TI activation. t-SMC induces antitumoral myelopoiesis with metabolic and epigenetic reprogramming in splenic macrophages. This shift toward antitumoral myelopoiesis markedly enriches the tumor microenvironment with inflammatory myeloid effectors in an E.G7-OVA model, and the adoptive transfer of splenic myeloid cells confirmed the TI-driven antitumor effect. Furthermore, comparative analysis revealed that the bacterial scaffold (alb-Mycobac) initiates myeloid reprogramming, but only the integrated TLR7/8 agonist (t-SMC) crosses the therapeutic threshold for tumor regression. In the MC38 surgical recurrence model, preoperative t-SMC combined with standard adjuvant αPD-L1 plus oxaliplatin achieved complete inhibition of recurrence in 50% of treated mice (3 of 6) with 62.5% long-term survival, establishing TI priming as a translation-ready preoperative adjuvant that converts immune-checkpoint non-responders into responders.