Incoherent light-emitting structures are of key interest for many fields in optoelectronics and spontaneous emission is the physical phenomenon underlying their light emission process. In this paper, we propose a novel full-matrix algebraic framework for modeling spontaneous emission modification from radiating electric dipoles in layered media. This formalism generalizes the standard 2 × 2 transfer-matrices into a compact 3 × 3 framework, which thus allows to treat dipole radiation directly into the matrix formulation as a source matrix. Its accuracy has been confirmed by incoherent 3D-FDTD. It has then been extended to complex emitter regions with both spectral and spatial distributions using incoherent combination. Finally, we applied this approach to various examples to demonstrate its applicability. Since it only requires modest computational efforts, we hope that this model can help better understand spontaneous emission dynamics in layered media and thus pave the way to novel design guidelines for devices in many fields of optoelectronics.