Chiral soliton lattices (CSLs) emerge from the competition between Dzyaloshinskii–Moriya interaction, anisotropy, and magnetic fields. While well established in monoaxial helimagnets, their role in materials with anisotropic, direction-dependent chirality remains poorly understood. Here, we report the direct observation of a crossover from π to 2π soliton lattices in the non-centrosymmetric Heusler compound Mn_1.4PtSn. Combining Lorentz transmission electron microscopy, resonant elastic X-ray scattering, and micromagnetic simulations, we identify a π-CSL as the magnetic ground state—rather than the expected spiral phase—which evolves into a classical 2π-CSL under increasing out-of-plane fields. This transition is governed by an interplay between uniaxial magnetocrystalline anisotropy and magnetostatic interactions, qualitatively captured by a double sine-Gordon model. Our framework extends to materials with D_2d, S₄, C_nv, or C_n symmetries in the thin-film limit, providing a unifying route to engineer magnetic phase diagrams in chiral systems with implications for soliton-based spintronics and topological transport.