Mr William Campbell was born in Belfast, Ireland (modern-day Northern Ireland) in the closing months of 1890.
Coming from a Presbyterian family, William was the youngest child of William Campbell (b. 1845), a seaman, and his wife Sarah, née Hawthorne (b. 1847). His father was apparently from Belfast whilst his mother hailed from Island Magee near the port of Larne in Co Antrim. The couple were married in Belfast in 1870 and went on to have eight children, losing two in infancy. Their known children, besides William, were: Mary Hawthorne (1871-1877), Elizabeth Corry (1873-1912), Sarah (b. 1876), Mary (b. 1878), Robert John (b. 1883) and Jane (b. 1886).
The 1901 census shows William and his family living at 47 Spamount Street in the New Lodge area of north Belfast. By the time of the 1911 census, the family have shifted to 45 Earl Street in Clifton, also in north Belfast and William is described as a joiner. The family later moved to 28 Earl Street.
William was one of the nine-strong "guarantee group" of Harland and Wolff employees chosen to oversee the smooth running of the Titanic's maiden voyage.
William Campbell died in the sinking and his body, if recovered, was never identified. Just one day after his death his elder sister Elizabeth Leathem died aged 38; she was buried in Belfast's City Cemetery on 18 April.
Campbell's estate, worth a meagre £10, was administered to his father William on 28 March 1913. On 15 April 1913 a memorial appeared in the Belfast Newsletter:
CAMPBELL--In fond and loving memory of my dear brother Willie, who lost his life in the R.M.S. Titanic on the 15th April, 1912; also my dear sister Lizzie (Mrs Leathem), who died the following day, and was interred in the City Cemetery.
William's mother later lived at 84 Corporation Street, Belfast and she died on 20 June 1915.