Iron-based high-temperature alloys are engineered to withstand extreme conditions, including elevated temperatures, mechanical stress, and corrosive environments. These alloys play a critical role in industries such as aerospace, power generation, and chemical processing, where materials must maintain structural integrity and performance under demanding operational conditions. This review examines recent advancements in iron-based alloys, with a focus on alloying strategies, high-temperature performance, and applications. Traditional approaches—including alloy design, microstructure control, process optimization, and computational modeling—continue to enhance alloy performance. Furthermore, emerging technologies such as high-entropy alloy (HEA) design, additive manufacturing (AM), nanostructured design with nanophase strengthening, and machine learning/artificial intelligence (ML/AI) are revolutionizing the development of iron-based superalloys, creating new opportunities for advanced material applications.