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The effect of the as-built microstructure and defect distribution on the fatigue performance of a metastable austenitic stainless-steel fabricated by directed energy deposition was analyzed in two fatigue regimes. Strain localization, porosity, microstructural response, and deformation induced phase transformation were studied for samples parallel and perpendicular to the build direction using digital image correlation, optical surface imaging, scanning electron microscopy, x-ray diffraction and electron back scatter diffraction. Pore area fractions between 0.3 and 0.6% played a negligible role in overall fatigue life. Anisotropic fatigue behavior and strain ratcheting were discovered in both fatigue regimes and connected to a high <100> texture and α^Ms_bcc formation in deformed samples with parallel orientations. Areas of localized strain and slip traces were linked to eventual crack initiation sites, and ultimate fatigue …