Olney entered into practice with his father in Olney & Olney, and then Olney, Pringle & Mannon. He also from 1895 to 1904 taught law classes at Hastings and when Berkeley opened its law school he lectured on evidence there from 1904 to 1907. In 1907, he joined the firm of Page, McCutchen, Knight and Olney, later known as McCutchen, Olney, and Willard (1913-1919). From 1911 to 1919, he was counsel for the regents of the University of California. In November 1920, he was re-elected but left the court after a time to resume private practice with McCutchen, Olney, Mannon, and Greene (1921-1939)(later known as McCutchen, Doyle, Brown & Enersen and then
Bingham McCutchen, until its collapse in 2014). In 1930 to 1932, he was a special assistant to the
Attorney General of the United States in
antitrust litigation concerning the
Radio Corporation of America. ==Bar and civic activities==