In this work, we study the ${\Omega }_c$ baryon spectrum up to the $2P$ excitations within a semi-relativistic constituent quark potential model, where the mixing between different configurations with the same spin-parity numbers is dynamically considered. Furthermore, the strong decay properties for the excited ${\Omega }_c$ states are evaluated within an improved chiral quark model by including the relativistic correction term. In a unified framework, we provide a reasonable explanation of the widths, masses, and mass splittings, for the newly observed ${\Omega }_c$ resonances ${\Omega }_c(3000)$, ${\Omega }_c(3050)$, ${\Omega }_c(3065)$, ${\Omega }_c(3090)$, ${\Omega }_c(3120)$, ${\Omega }_c(3185)$, and ${\Omega }_c(3327)$. It is found that the configuration mixing is crucial for understanding the strong decay properties and mass splittings, while the relativistic correction term of the strong transition operator plays an important role in the states dominated by the radial excitations. We expect our study can provide useful references for establishing a more abundant ${\Omega }_c$ spectrum.