Holabird was the son of General Samuel B. Holabird and Mary Theodosia Grant. He studied at the United States Military Academy at West Point but resigned and moved to Chicago, where he later got married.
He worked in the architectural practice of William Le Baron Jenney next to O. C. Simonds. Shortly after receiving the commission to extend Graceland Cemetery, Jenney passed it on to his assistants who, in 1880, established the firm of Holabird & Simonds to carry out this job. In 1881, Martin Roche, who had also worked in Jenney's office, joined them as a third partner. In 1883 the firm was renamed Holabird & Roche after Simonds left to concentrate solely on Graceland Cemetery and landscape design.
Together they contributed many innovations to the architecture of the time, especially in what is now referred to as Chicago School. They designed several influential buildings, including the Marquette Building and the Gage Building. The latter included a façade designed by Louis Sullivan and was cited a Chicago architectural landmark in 1962.
William's sister Agnes Holabird Von Kurowsky was the mother of Agnes von Kurowsky.
- Bruegmann, Robert. The Architects and the City: Holabird & Roche of Chicago, 1880-1918. Chicago, IL: The University of Chicago Press. p. 7. ISBN 978-0-2260-7695-9.
- Julia Sniderman Bachrach, Ossian Cole Simonds: Conservation Ethic in the Prairie Style, in: William H. Tishler (Ed.), Midwestern Landscape Architecture, University of Illinois 2000.
- Robert Bruegmann, Holabird & Roche, Holabird & Root. An illustrated catalog of works, Garland (New York) in cooperation with the Chicago Historical Society 1991.
- Robert Bruegmann, The architects and the city. Holabird & Roche of Chicago, 1880-1918, University of Chicago Press 1997.