We report a case of acquired thrombotic microangiopathy (TMA) precipitated by an influenza A virus subtype H1N1 infection. In March of 2023, a 67-year-old man, diagnosed with relapsed and refractory multiple myeloma, developed a fever immediately following a carfilzomib infusion. The following day, he tested positive for influenza A virus subtype H1N1 via a real-time polymerase chain reaction. Two days later, he exhibited unexplained thrombocytopenia, followed by typical clinical signs of microangiopathic hemolytic anemia, leading to a diagnosis of TMA. Treatment included oseltamivir, dexamethasone, plasma exchange therapy, and eculizumab. Remarkably, 35 days post-admission, the patient fully recovered and was discharged. This case indicates a potential link between influenza A virus subtype H1N1 infection and the onset of acquired TMA, with carfilzomib possibly elevating the risk.