Mixed Mode Polymerization (MMP) is introduced and defined as any polymerization process that combines chainwise and stepwise mechanisms, which both contribute to the growth and structure modification of its polymer product. The large difference in activation energies of the growth steps of these two mechanisms provides great flexibility for polymer property control. A large variety of possible combinations including these mechanisms can be designed, which leads to a diversity of processes that require the development of a unified treatment technique. Building on the well-established theories and modeling frameworks available for free-radical polymerization and polycondensation, a generalized approach for modeling MMP is developed. Example applications of the technology are discussed and a case study is analyzed to illustrate the applicability of the generalized modeling approach.