Stanley James May was born on 25 August 1866 in Middlesex, England, the son of Richard William May (1832-187) and Susan Ellen Mann (1833-1913). His father had risen from being a porter to becoming a successful fishmonger at Billingsgate fish market.

He had six siblings: Richard William May (1858–1938), Philip Charles May (1859–1900), Walter Moss May (1861–1893), Susan Amy May (1868–1950), Lily May (1871–1966) and Fred May (1872–1936)

Stanley trained as an architect.

In 1894 he married Emily Jane Cridlan (1864-1913) and they had five children: Hilda May (1896–1966), Gladys May (1899–), Wilfred May (1901–1982) and Irene May (1904–1984), the fifth child died in infancy.

Stanley May boarded the Titanic at Southampton as a first-class passenger, together with his brother Richard, sister Lily, her son Jack and her sister-in-law Kate Odell.  Lily's husband Herbert had booked six berths so it is possible he originally intended to accompany the party.  The party were going on a motoring holiday in Ireland.

While onboard Stanley wrote to his daughters Hilda and Gladys describing the ship as a palace and noting how they were delayed arriving at Cherbourg owing to the New York incident which Kate Odell photographed. 

The group disembarked the Titanic at Queenstown. The following year Stanley was widowed. His wife Emily dying on 6 January 1913.

Stanley J. May died in Twickenham on 9 July 1946.