He was born in 1863 at 5, Crombie's Row, Mile End Old Town (not Wapping, as is often stated),[1] London, to William Gage Jacobs, wharf manager, and his wife Sophia.

[2] His father managed the South Devon wharf in Lower East Smithfield, by the St Katherine Docks and, according to the Oxford Dictionary of National Biography, "the young Jacobs spent much time on Thames-side, growing familiar with the life of the neighbourhood" and "ran wild in Wapping".

His favourite subject was marine life – "men who go down to the sea in ships of moderate tonnage", said Punch, reviewing his first collection, Many Cargoes,[8] which gained popular success on publication in 1896.

Michael Sadleir has said of Jacobs's fiction, "He wrote stories of three kinds: describing the misadventures of sailor-men ashore; celebrating the artful dodger of a slow-witted village; and tales of the macabre.

The title of the last reflects the popularity of an enduring character: the night-watchman on the wharf in Wapping, recounting the preposterous adventures of his acquaintances Ginger Dick, Sam Small, and Peter Russet.

The 1901 Census records their living with a first child, a three-month-old daughter, at Kings Place Road, Buckhurst Hill, Essex.

Also recorded in the household were his journalist sister Amy, his sister-in-law, Nancy Williams, a cook, and an additional domestic servant.

Another blue plaque appears on Jacobs's central London residence at 15 Gloucester Gate, Regents Park (later held by the Prince of Wales's Institute of Architecture).

[5] On 7 January 1914, in King's Hall, Covent Garden, Jacobs was a member of the jury in the mock trial of John Jasper for the murder of Edwin Drood.