C. Louis Borie, Jr. (but really II), was born in Philadelphia to Beauveau and Patricia Duffield (Neill) Borie. In Philadelphia he attended the Faires Classical Institute, entering there in 1881 and leaving in 1884, when he entered St. Paul's School in Concord, NH. After graduation from St. Paul's, young Borie attended the University of Pennsylvania in its course in civil engineering. He did not, however, graduate with the Class of 1892 because he left school following his junior year. His degree, in fact, was conferred on him in 1907 when the University implemented a policy of awarding degrees to those students who had been forced to leave before finishing their intended courses of study.
By 1894 Borie was working in his father's banking enterprise, C. and H. Borie, bill brokers with offices at 121 South 5th Street, where he remained until 1902. At that time he joined C. C. Zantzinger in a firm which was formally named Zantzinger & Borie by 1905. The partners were subsequenty joined by Milton B. Medary and practiced as Zantzinger, Borie & Medary until Medary's death in 1929. Following Medary's death, the firm reverted to Zantzinger & Borie. Although it would be easy to assume that Borie served as a business partner only in the two firms with which he was associated, that assumption would be misleading. In a letter dated 7 July 1915 and written by C. C. Zantzinger in support of Borie's membership in the AIA, his partner states that it was Borie's idea to site the Philadelphia Museum of Art atop an "acropolis" which would be surrounded by Philadelphia institutions of art instruction. (This letter was discovered in the membership Archives of the American Institute of Architects.) Certainly Borie's training as an engineer would combine with business expertise to the benefit of both architectural firms.
Charles Louis Borie, Jr., was extremely active in both professional and social organizations. As an undergraduate at the University he had been one of the founders of the Mask and Wig Club; later he served on the University's Board of Fine Arts. He became a member of the national AIA in 1908 and was elevated to fellowship status in 1915. He was also a member of the T-Square Club, serving on various committees from 1907 to 1935. In addition, Borie was chair of the Art Commission of the Smithsonian Institution in Washington, DC, and spent one term as an architect member of the National Commission of Fine Arts. During the 1930s he was particularly active in organizational pursuits, including operating as technical advisor to the Philadelphia Housing Authority (1933), contributing to the Pennsylvania State Public Works Advisory Board (1933), and representing the United States at the Eighth International Conference of Design and Applied Arts in Paris (1937). On a more local level Borie served as chairman of the Fairmount Park Art Association.
Borie was made a Fellow of the American Institute of Architects in 1915, at the same time that Warren Powers Laird received that distinction.