Infectious diseases are emerging and spreading at unprecedented rates, affecting wildlife worldwide. Since the introduction of avian malaria to Hawaii a century ago, the disease has contributed to the decline and extinction of several endemic Hawaiian honeycreeper species. Evidence suggests that populations of one honeycreeper species, the Hawaii Amakihi (Hemignathus virens), that have experienced strong selection by avian malaria have evolved resilience to the disease. However, the mechanisms of avian malaria resilience, as well as the consequences of resilience and chronic infection on bird health, remain poorly understood. The goals of this study were to examine the role of innate immunity in malaria resilience and determine the effects of resilience and chronic infection on Amakihi health. To do so, we measured the innate immunity and health of infected and uninfected free-living Amakihi from low elevation populations, which have experienced strong election by avian malaria, and high elevation populations, which have experienced weak selection by the disease. As expected, measures of innate immunity were higher in low than high elevation Amakihi, although these relationships were dependent on environmental context. Regarding measures of health, results were mixed. Body condition was higher in high than low elevation birds, but only on the leeward side of the island, and higher in malaria infected than uninfected Amakihi. Hematocrit was higher in high than low elevation individuals but, surprisingly, did not vary by malaria infection status. These are among the first results to describe phenotypic differences related to the immune function and health of Amakihi varying in avian malaria resilience and infection.