This paper presents results of a near-infrared imaging survey for low-mass stellar and substellar companions to white dwarfs. A wide-field proper-motion survey of 261 white dwarfs was capable of directly detecting companions at orbital separations between 100 and 5000 AU with masses as low as 0.05M_{sun}_, while a deep near-field search of 86 white dwarfs was capable of directly detecting companions at separations between 50 and 1100AU with masses as low as 0.02M_{sun}_. Additionally, all white dwarf targets were examined for near-infrared excess emission, a technique capable of detecting companions at arbitrarily close separations down to masses of 0.05M_{sun}_.