Transition metal dichalcogenides (TMDs) intercalated with spin-bearing transition metal centers are a diverse class of magnetic materials where the spin density and ordering behavior can be varied by the choice of host lattice, intercalant identity, level of intercalation, and intercalant disorder. Each of these degrees of freedom alters the interplay between several key magnetic interactions to produce disparate collective electronic and magnetic phases. The array of magnetic and electronic behavior typified by these systems renders them distinctive platforms for realizing tunable magnetism in solid-state materials and promising candidates for spin-based electronic devices. This Perspective provides an overview of the rich magnetism displayed by transition metal-intercalated TMDs by considering Fe- and Cr-intercalated NbS2 and TaS2. These four exemplars of this large family of materials exhibit a wide range of magnetic properties, including sharp switching of magnetic states, current-driven magnetic switching, and chiral spin textures. An understanding of the fundamental origins of the resultant magnetic/electronic phases in these materials is discussed in the context of composition, bonding, electronic structure, and magnetic anisotropy in each case study.