Cornwall was born in Lapford, Devon. At the age of thirteen he became a clerk in a coal merchant's in Hammersmith, London, and by seventeen was manager of the company's depot at Kensington. A few years later he set up his own business. In 1900 he became the first mayor of the new Metropolitan Borough of Fulham, having long served on the predecessor vestry. In 1892 he was elected to the London County Council, sitting for the Progressive Party, for which he was for eight years chief whip. In 1904 he was elected chairman of the LCC and as chairman of the Parliamentary Committee of the council led efforts to clear the slums between Holborn and the Strand on the site of which were built Aldwych and Kingsway.
Having unsuccessfully contested the Fulham constituency in 1895 and 1900, in 1906 Cornwall was elected to Parliament as a Liberal for Bethnal Green North East. He was appointed a deputy lieutenant of the County of London at the end of March 1906. From December 1916 to February 1919 he served as Minister of National Health Insurance and Comptroller of the Household and from 1918 to 1922 he was Deputy Chairman of Ways and Means and Deputy Speaker of the House of Commons. He was also vice-chairman of the County of London Territorial Force Association from 1908 to 1914 and a member of the Port of London Authority.
- "Cornwall, Rt Hon. Sir Edwin". Who Was Who. Oxford University Press. December 2007. Retrieved 2 May 2011.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
- "Obituary: Sir Edwin Cornwall". The Times. 2 March 1953. p. 10.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
- Debrett's Illustrated Heraldic and Biographical House of Commons and the Judicial Bench (PDF). London: Dean & Son. 1916. pp. 37–38. Retrieved 12 May 2009.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
- "The London County Council Election". The Times. 7 March 1892. p. 10.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
- The London Gazette: . 6 April 1906.
- The London Gazette: . 17 November 1905.
- The London Gazette: . 30 August 1918.
- The London Gazette: . 4 June 1921.
- Hansard 1803–2005: contributions in Parliament by Sir Edwin Cornwall
|Parliament of the United Kingdom|
Sir Mancherjee Bhownagree
|Member of Parliament for Bethnal Green North East
John Williams Benn
|Chairman of the London County Council
Charles Henry Roberts
|Comptroller of the Household
George Frederick Stanley
|Baronetage of the United Kingdom|
(of Holcombe Burnell)