Successive waves of political turbulence during the early Qing dynasty had a profound impact on the Chinese hereditary mathematician families of the Astronomical Bureau, who since the late Ming had been deeply involved in a crisis over calendar reform. This paper focuses on the important early Qing court mathematician He Guozong's 何國宗ancestors, particularly his father's generation and the two previous generations. Despite the difficult circumstances they faced in the Astronomical Bureau, the He family mathematicians sought to advance their careers in different ways, laying the foundations for the family's future. This paper reinvestigates the He family mathematicians' involvement in the dispute over calendar-making methods, in particular the New Western and Great Concordance methods, revealing the roles of the Kangxi Emperor and the He family in prolonging and finally ending the dispute.