Ḥasan ibn Jahm is regarded as one of the prominent and reliable companions of the two Imams, Imam Kāẓim (AS) and Imam Riḍā (AS). In the Rijāl sources, he is described with titles such as trustworthy, distinguished authority and eminent. The present study adopts a descriptive-analytical methodology based on library research and a comparative examination of both biographical and hadith sources. Within this framework, the Rijāl status and the chain of transmission position of Ḥasan ibn Jahm are analyzed, while the thematic patterns and content categories of his narrations in the Four Canonical Shiʿi Hadith Collections are examined. The findings indicate that Ḥasan ibn Jahm is recognized as a reliable transmitter within the Imami tradition, whose narrations encompass a wide range of themes, including theological, ethical, jurisprudential, devotional, and educational subjects. The thematic analysis of these narrations reveals the presence of fundamental ideas such as monotheism, the doctrine of Imamate, the role of reason, spiritual purification, the etiquette of supplication, avoidance of extremism and excessive asceticism, and the observance of social ethics. His direct dialogues with Imam Riḍā (AS) further demonstrate his intellectual and scholarly standing, and his narrations exemplify a rational interaction between the narrator and the Imam in the transmission of divine teachings. The results of this research suggest that Ḥasan ibn Jahm should be considered among the influential transmitters who served as a link between the hadith school of Imam Ṣādiq (AS) and the rational discourse that characterized the era of Imam Riḍā (AS). A reexamination of his narrations can therefore contribute significantly to a deeper understanding of the development of theological and ethical discussions during the early centuries of Shiʿism.