In 1921, Sakaki Yasusaburō, a professor of psychiatry at Kyushu Imperial University, introduced to Japanese audiences a rejuvenation method invented by the Austrian physiologist Eugen Steinach. Four years later, Sakaki was forced to resign from his position due to an embezzlement scandal, leading to the academic repudiation of his rejuvenation studies. This paper investigates the reasons behind this decline and identifies the role of popular media in shaping the professional identities of biomedical researchers in post-WWI Japan. It argues that a series of confrontations concerning the rules and norms of academic behavior that eventually led to Sakaki being labeled a “traitor” to his profession was as much influenced by the popular media as by considerations of scientific rigor. Highlighting the previously understudied interaction between popular media and its impact on the professionalization of biomedical research in modern Japan, this paper reveals the active and multiple roles that popular media plays in determining legitimate research topics and appropriate conduct for biomedical researchers.