Rare-earth nickel dicarbides attracted attention, because of interesting properties such as super-conductivity, magnetism, multiple charge density wave (CDW) transitions related to quasi-one-dimensional electronic features, and finally, a complex interplay of CDW order and rare earth magnetism. Here, we report on single crystal studies of thermodynamic bulk properties such as heat capacity and magnetic susceptibility of DyNiC2 which are combined with powder inelastic neutron scattering studies conducted at the MAPS instrument at the ISIS neutron spallation source to analyse the crystalline electric field (CEF) splitting of the Kramers-type (J=15/2) 4f9 state of DyNiC2 in terms of a full CEF model. The latter is essential to further explore the peculiar quasi-quartet magnetic ground state of DyNiC2 with two consecutive second order phase transitions, each releasing the entropy related to one CEF doublet state.