The magnetic properties of elastomers based on silicone matrix and iron microparticles assembled in linear chain-like aggregates of different length are experimentally investigated. For this purpose, elastomer samples with a low concentration of magnetic filler are structured in a magnetic field of various strength. The influence of the particle aggregates morphological characteristics on the macroscopic magnetic response of the samples is revealed. Moreover, the influence of the angle between the direction of particle aggregates, that is, the field applied in the process of crosslinking the polymer matrix, and the direction of the field applied during magnetic measurements on the macroscopic magnetic properties of the composite is taken into account. Magnetic measurements are supported by the evaluation of the real microstructure of the samples using X-ray computed microtomography and corresponding digital image processing methods.