Macromolecules bearing stable radical groups have emerged as extremely useful active materials in organic electronic applications ranging from magnetic devices to flexible batteries. Critical to the success of these open-shell polymers has been the readily tunable nature of their molecular architectures; this important molecular structure-property-performance design paradigm has allowed for significant device performance metrics to be achieved. In this Perspective, the recent advancements regarding the design and device functionality of a common class of open-shell macromolecules, radical polymers, are discussed. Here, radical polymers are defined as macromolecules with nonconjugated carbon backbones, whose optoelectronic functionalities arise due to the presence of stable radical sites on the pendant groups of macromolecular chains. This class of materials provides a unique platform for the design of unique optical and electronic properties in soft materials; however, as with many organic electronic materials, transitioning these gains from the laboratory to the commercial scale remains a primary challenge. As such, we provide context for the significant accomplishments that have been made in the field, describe how these advances have been translated to high-performance devices, and discuss future areas of evaluation for these next-generation polymer electronic materials.