McClellan was AIEE president from 1921 to 1922.
A casual glance over the record of the youth and young manhood of William McClellan would make it appear that he was destined for an academic life; as a matter of fact this academic experience formed an excellent basis for his later career as a prominent engineering an economist in the electric traction and public utilities fields.
He was burn in Philadelphia in 1872 and graduated from high school at 17 years of age, taking a postgraduate course in electrical engineering the following year. He was an assistant in engineering for 1 year at Swarthmore college, and then taught mathematics and physics in the high schools of Philadelphia for 7 years. At the same time he studeied at the University of Pennsylvania for the B.S. degree, which he received in 1900; in 1903 he received the Ph.D. degree. He was instructor in electricity and magnetism in the department of physics at the university from 1900 to 1905. A number of years later he returned to the university as dean of the Wharton School of Finance and Commerce, and in later years continued his connection wit the university ad director general of the alumni society and as trustee.
From 1900 to 1904 Doctor McClellan also worked in various capacities for the Union Traction and Philadelphia Rapid Transit companies, some of his important assignments being the erection of a large car barn and the rebuilding of a large power house, including erection of engines, boilers, generators, motors, lighting switchboards, cables, etc. In 1905 he went to New York to do responsible design work for the Westinghouse Church, Kerr and Company on the lighting and power distribution for the Pennsylvania Railroad terminal. he also had charge of the layout and installation of a high-voltage substation and the car equipment for the Erie Railroad, and was design consultant of the Edison Illuminating plants at Brockton, Mass.
From 1907 to 1916 Doctor McClellan was vice-president of the Campion McClellan Company and was responsible for all the mechanical and electrical engineering design, and construction handled. He drew up numerous reports on power plants and water power developments and took charge of the complete mechanical and electrical equipment and installations for various manufacturing plants. From 1915 to 1920 he was a member of the firm, Paine, McClellan and Campion. Between 1919 and 1921he was vice-president of the Cleveland Electrical Illuminating Company. In 1922 he became a member of the firm of McClellan and Junkersfeld, remaining in this firm until in 1929 he was elected vice-president of Stone and Webster Engineering corporation. At present he is president of William mcClellan and Company, Ltd. and of the Potomac Electric Power Company of Washington D.C.
He was consulting engineer for the Public Service Commission of the 2nd district, New York State, from 1911-13 and a member of the President's commission on Muscle Shoals in 1912. During the war he was director of the intercollegiate intelligence bureau in Washington. He has served the Institute over a long period of years as officer and committeeman.