Microstructural and ferromagnetic resonance properties of epitaxial nickel ferrite (NiFe2O4) films grown by direct liquid injection chemical vapor deposition are reported. While high-quality epitaxial growth of NiFe2O4 films on (100)-oriented MgAl2O4 substrate is confirmed by high resolution transmission electron microscopy, bright field (diffraction contrast) TEM studies reveal the presence of dislocations and also dark diffused contrast areas, which originate from antiphase domains. Angle and frequency-dependent ferromagnetic resonance (FMR) experiments are conducted to determine the magnetic anisotropy and the magnetic relaxation. A low out-of-plane FMR linewidth of 160 Oe has been observed at a frequency of 10 GHz.