This article focuses on the relationship between the controversial late-Ming playwright Tu Long and the contemporaneous Tiantai school of Buddhism represented by Youxi Chuandeng. It aims to contribute on the one hand to studies of Tu Long, which have paid little attention to Tu's connection with Tiantai, and on the other hand to studies of Chuandeng and the late Ming Tiantai revival, which have not yet explored the nexus between Chuandeng's philosophical teachings and his social network. I argue that it is most likely through Tiantai Buddhism, rather than "mad Chan" or Yangming philosophy, that Tu justified his antinomian deeds. This case study of Tu Long indicates that the success of the Tiantai school in the late Ming may be attributed to its fulfillment of the literati appetite for reading and writing, as well as to its tolerance of their unconventional lifestyle and syncretic spirituality. Unveiling some disagreements between Tu and Yunqi Zhuhong, whom many regard as Tu's guru, this paper highlights the agency of a lay Buddhist amid the tensions between rival schools and teachers.