The law attracted Thomas Peebles but could not confine his many interests and boundless energy. Born in Ireland, he arrived in America at age thirteen; he worked his way through Princeton University, graduating in 1882; he then taught philosophy at the University of Minnesota for five years while helping coach the school's first football teams.
Attracted to the law, he left academia, was admitted to the Minnesota bar on April 16, 1886, and began practicing in Minneapolis. He developed a corporate clientele, and served as a director on the boards of several corporations. He was an active investor and advisor as well. In the last chapter of his life, he and his sons formed a construction company that built hundreds of homes in Minneapolis.
He died on March 10, 1938, at age eighty-one. On February 11, 1939, Edward C. Gale delivered a tribute to him in Hennepin County District Court on behalf of the county bar association.