James Madison Power Wallace was born in Philadelphia in 1847 to Henry Edward Wallace and Hetty Dungan Potts.
Wallace entered the University of Pennsylvania in 1861 as a member of the Class of 1865, and was a second cousin of classmate Robert Emmet McDonald. Wallace was an enthusiastic member of the Zelosophic Society, serving as vice regent in his senior year and composing poetry vilifying the rival Philomathean Society.
After graduation from the College, Wallace studied law at the University. He became a lawyer and also, from 1869-1891, the publisher of the Legal Intelligencer. On December 12, 1872, he married Sarah Matilda Shreve. He died in Philadelphia in 1907.
Wallace kept a comprehensive scrapbook of his years at the University and of subsequent class events; the material was eventually donated to the University Archives by his son, John Small Wallace, who graduated from the Penn Law School in 1898.