Charles Clegg was born in Manchester, England on 12 December 1828 and was articled to Edwin Hugh Shellard for five years. He commenced practice as an independent architect in Manchester in 1851, and that year formed a partnership, Clegg & Knowles, with John Knowles (1830-1879) which continued until Knowles's death. In 1882 Clegg's son, Charles Theodore Clegg (1861-1930) joined the practice. Not long after that they were joined by Knowles' son Frederick Knowles (1859-?). By 1884 the practice had been re-named Clegg Son and Knowles. In 1885 Knowles resigned from the practice which then became Charles Clegg & Son.
Charles Clegg was elected a Fellow of the Royal Institute of British Architects (FRIBA) in 1907. He died in Bucklow, Cheshire on 22 May 1922.
Directory of British Architects 1834-1914. Compiled by Antonia Brodie, et al. Volume 1: A-K. London; New York: British Architectural Library, Royal Institute of British Architects/Continuum, 2001