During his early years, he was educated in Catholic schools and while he has expressed his desire to serve as a De La Salle Brother, his father did not allow him to do so.
In 1909 he was posted at the Christian Brothers school in Hartford, Connecticut, and in 1911 he was assigned to St. John's Academy in Utica, New York.
Peter also donated the marble altar of the new College's chapel, which he financed from the inheritance that he received.
In 1927 he was reassigned to Manila to teach Mathematics in the high school department and then back again to Penang as Sub-Director of the Junior novitiate.
In 1951, the De La Salle Brothers in the Philippines opened a novitiate and Graves was appointed Sub-Director and taught Theology and Church History, among other subjects.
On November 23, 1968, Graves was brought to the Manila Medical Center after complaining of chest pains and died four days later.