Mr William McCastlin was born in St John, New Brunswick, Canada around late 1883 or early 18841, the son of William and Mary McCastlin.
Little is known of McCastlin's background or life and he and his family are not readily identifiable on the 1891, 1901 or 1911 Canadian censuses. He is known to have been Roman Catholic and was perhaps of Irish ancestry.
He first appears on record in Britain in March 1905 when he was serving as a fireman aboard Cearense, operating out of Liverpool and with him giving his address as 8 Atlantic Avenue, Brooklyn. Later that year he was shown on several voyages aboard the ships Calvin Austin and Salem Austin which were operating between Boston and New Brunswick; the immigration papers associated with these voyages describe McCastlin as aged 22 and standing at 6' and with light hair, blue eyes and a light complexion.
He was married in St John's Cathedral in his native New Brunswick on 23 November 1906 to Agnes McClusky (b. 18 July 1885), daughter of John and Catherine McClusky, the latter née McKeever who were also of Irish ancestry; their residence was given as St Patrick Street and William's profession as a sailor.
William and Agnes had two sons: William Francis (b. 19 February 1906) and Joseph Leo (b. 9 March 1910).
Back in Britain and by late 1908 McCastlin was still serving aboard Cearense; over two voyages in 1910 he was still specifying his address as 8 Atlantic Avenue and by which time he was described as a fireman and storekeeper.
McCastlin signed on to the Titanic in Southampton on 6 April 1912 and gave his local address as 53 French Street, Southampton and his previous ship as the Oceanic. As a fireman he could expect monthly wages of £6.
William McCastlin died in the sinking and his body, if recovered, was never identified.
His widow Agnes was remarried in early 1913 to John Clarke Briggs (b. 1875) and went on to have at least four more children. She remained in St John, New Brunswick where she died on 6 September 1953 and was buried in St Joseph's Cemetery in St John.
Son William died aged 95 on 1 May 2001 and was also buried in St Joseph's Cemetery.
What became of son Joseph is not clear.