Marwood was originally a cobbler, of Church Lane, Horncastle, Lincolnshire, England.
At the age of 54 he persuaded the governor of Lincoln Castle Gaol to allow him to conduct an execution. The efficient way in which he conducted the hanging of William Frederick Horry without a hitch on 1 April 1872 assisted him in being appointed hangman by the Sheriffs of London and Middlesex in 1879, in succession to William Calcraft, at a retainer of £20 a year plus £10 per execution.
The "Long Drop"
Marwood developed the "long drop" technique of hanging, which ensured that the prisoners' neck was broken instantly at the end of the drop, resulting in the prisoner dying of asphyxia while unconscious. This was considered somewhat more kind than the slow death by strangulation caused by the "short drop" method, which was particularly distressing to prison governors and staff who were required to witness executions at close quarters following the abolition of public executions by the Capital Punishment Amendment Act 1868.
In his nine years as a hangman, Marwood hanged 176 people, including:
- William Frederick Horry, the first person to be hanged by William Marwood and the first person to fall using the long drop; hanged at Lincoln Castle, Lincolnshire on 1 April 1872.
- Henry Wainwright, a brushmaker who murdered his mistress Harriet Lane in September 1874 and buried her body in a warehouse he owned. When he was declared bankrupt the next year, he disinterred the body in September 1875 and was arrested attempting to rebury it. He was hanged in Newgate on 21 December 1875.
- Charles Peace, the archetypal Victorian burglar and murderer, whose name struck terror in the hearts of everyone at the time; hanged at Armley Jail, Leeds, Yorkshire, on 25 February 1879. Marwood apparently met Charles Peace on a railroad journey a few years before the execution. Peace asked Marwood about his experiences. At the time of the hanging, Marwood reassured Peace he would make it fast and painless with the long drop method.
- Kate Webster, an Irish servant woman who murdered her employer; hanged at Wandsworth Prison, London, on 29 July 1879.
- Charles Shurety who viciously beat his common-law wife's young daughter to death in London; he was executed at Newgate Prison, London on 5 January 1880, after a failed attempt to stop the execution with a forged order from the Home Office.
- Percy Lefroy Mapleton, who murdered Isaac Frederick Gold on a train between London and Brighton for his watch and some coins; Mapleton was arrested almost immediately, but escaped before being arrested again, convicted, and hanged on 29 November 1881.
- Dr George Henry Lamson, who poisoned Percy Johns (his crippled brother-in-law) with aconitine at Wimbledon so his wife could inherit some money. Lamson actually returned from France, certain he had covered his tracks; he was tried and convicted, and hanged at Wandsworth Prison on 28 April 1882.
- Joe Brady and four other members of the Irish National Invincibles gang who murdered Lord Frederick Cavendish, the Chief Secretary for Ireland, and Thomas Henry Burke, the Permanent Under-Secretary for Ireland, with surgical knives in Dublin's Phoenix Park; they were hanged at Kilmainham Jail in Dublin in 1883.
Marwood was one of two executioners to give their name to the character of the hangman in the British Punch and Judy puppet show (Jack Ketch being the better known one).
In Marwood's time there was a popular rhyme which went:
- If Pa killed Ma
- Who'd kill Pa?
- Free Reg Baptisms
- Brian P. Block, John Hostettler, Hanging in the balance: a history of the abolition of capital punishment in Britain, Waterside Press, 1997, ISBN 1-872870-47-3, pp. 38–39.
- James Conway Walter (1908). A history of Horncastle, from the earliest period to the present time. W.K. Morton. p. 155.
- Judith Flanders (2011). The Invention of Murder: How the Victorians Revelled in Death and Detection and Created Modern Crime. HarperCollins Publishers Limited. pp. 338–343. ISBN 0-00-724888-1.
- Horace Bleackley (1929). The hangmen of England: how they hanged and whom they hanged : the life story of "Jack Ketch" through two centuries. Taylor & Francis. p. 235. ISBN 0-7158-1184-3.
- Philip Lindsay (1939). A mirror for ruffians. Essay index reprint series (reprint ed.). Ayer Publishing. pp. 133–134. ISBN 0-8369-2799-0.
- Leonard A. Parry; Willard H. Wright (2000). Some Famous Medical Trials. Beard Books. p. 226. ISBN 1-58798-031-2.
- Howard Engel (1997). Lord high executioner: an unashamed look at hangmen, headsmen, and their kind. Robson Books. pp. 67–68. ISBN 1-86105-096-8.
- Adam, Hargrave L. (1955). "Dr George Lamson". In Hodge, James H. Famous Trials 5. Penguin. p. 179.
- Lost Lives: William Marwood Lost Lives: William Marwood, retrieved 20 August 2010.
- "Oxford DNB article: Marwood, William". www.oxforddnb.com. Retrieved 2010-09-14.
- Fullerty, Matt, 'The Murderess and the Hangman.' A biographical novel about Marwood's hangings of celebrated Victoria criminals Charles Peace and Kate Webster.
- Hargrave, Adam L. (ed.), Notable British Trials Series: Trial of George Henry Lamson (London, Edinburgh, Glasgow: William Hodge & Co., Ltd., 1912, 1951), pp. 210–13
- Browne, Douglas G., The Rise of Scotland Yard: A History of the Metropolitan Police, (London, Toronto, Wellington, Sydney: George G. Harrap & Co., Ltd., 1956), p. 181 (re Charles Shurety).
- Laurence, John, A History Of Capital Punishment (London: Sampson Low, Marston & Co., Ltd., ), pp. 114–20
- Parry, Leonard A., Some Famous Medical Trials (New York: Charles Scribners' Sons, 1928), p. 226 (re Charles Shurety)
- Crime Novel Becomes Reality for GW English Professor, GW English News, English Department, George Washington University, 28 October 2010
- Skull found in Sir David Attenborough's garden that solves 1879 Barnes murder mystery, Daily Mail, 25 October 2010
- How a skull found in David Attenborough's garden has solved one of Victorian Britain's most gruesome murder mysteries, Daily Mail, 26 October 2010